Human Biology

Ethical Essay

2008-12-12T20:50:00.000-08:00

www.un.org

Population vs Resources

With population growth at exponential rates, the question of who should reproduce can bring up more questions than answers. World population is currently increasing at a rate of nearly 75 million each year. Should we place limits on growth? Although we are creating fewer offspring in the US, there are more of us which accounts for the growth in population. As evidenced in China, the one child per couple campaign helped to curb population growth, but their yearly growth still exceeds 12 million per year.

Statistics generally indicate lower birthrates in developed countries and higher rates in developing countries. The higher rate of birth is associated with many factors. Lack of education about family planning and birth control methods, lifestyles that compliment larger families, or high infant mortality rates are some of the reasons. In some places the high incidence of infant mortality is offset by higher birth rates because of the eventual fear of losing a child. Thus in some areas birth rates actually exceed high mortality rates. As population density increases it's needs for resources inceases, and the greater the population the more competition there is for resources. As a result some countries have advocated incentives for parents with one or two children and others have suggested raising the marriage age.

Contrary to statistics of developed countries, the US has one of the highest natural population increases for industrialized nations with no relief in sight. The US is also the largest energy consumer in the world in terms of total use. This impacts our immediate as well as the global environment. It is said that a typical US child will consume the equivalent of 300 children in Ethiopia. This brings to question the environmental impact of populations in regards to quality as opposed to quantity.

According to the scientific community consensus on carrying capacity greatly vary. Some claim that carrying capacity should be tossed out altogether because the increase in population will provide the creativity and innovation to support this increase or that technology will keep pace with these dilemmas.

From an ecological viewpoint some countries are challenging their biological capacities. The addition of another individual doubles the environmental footprint placed on the environment. That is the amount of land it takes to support a person's lifestyle. Because resources are essentially limited, how will we account for this increase in population.

There are many sides to this issue and some experts propose that the overuse and decay of resources is a natural process that will eventually correct itself. Others suggest that extinction is also a natural process of the cycle, as it has happened numerous times before.

As evidenced from different perspectives, both population and energy consumption impact the environmet. Because of this it would seem beneficial that both the management of resources and the management of population growth be looked at to ensure the sustainability of life on this planet. The ways we use our resources and treat our waste products will affect our quality of life. For instance, our demand to grow food in large quantities has benefited us by having a readily available food source and yet some methods also endanger the soil environment which can conversely reduce yields. Thus, careful use of our resources and controlling population growth both have important roles to ensure lasting resources for future generations.

As population and alteration of resources have contributed to pollution and other unwanted environmental effects, complex issue arise that are intertwined in politics, economic, cultural, and social affairs. Many issues related to these factors will continue to affect our lives. Given the current trends it is unlikely that a reversal can occur without some intervention.Therefore steps to avert depletion and over-consumption will continue to be an area of growing concern.

References:

http://afe.easia.columbia.edu/china/geog/population.htm

http://www.footprintnetwork.org/en/index.php/GFN/page/footprint_for_nations/

http://www.globalchange.umich.edu/globalchange2/current/lectures/human_pop/human_pop.html

http://www.globalissues.org/issue/198/human-population

http://en.wikipedia.org/wiki/Energy_use_in_the_United_States

2008-12-12T12:04:00.000-08:00

Self Evaluation

What were the three aspects of the assignments I've submitted that I am most proud of?

The species lab assignment, because it offered a different way of viewing our immediate environment. The chapter on fetal development, because it is an interesting topic and the compendium reviews because it pulls everything together.

What two aspects of my submitted assignments do I believe could have used some improvement?

It is difficult to load photos sometimes and figuring out where they will end up on the page.

What do I believe my overall grade should be for this unit?

I hope to get a A- or B+.

How could I perform better in the next unit?

There isn't another unit, but hypothetically it would be preparation.

At what moment during this unit did you feel most engaged with the course?

Putting together the concepts from the textbook and the powerpoint slides.

At what moment did you feel most distanced from the course?

Had difficulty opening some pages.

What action that anyone (teacher or student) took during this unit that you find most affirming and helpful?

The learning center staff were helpful. Saved pages on the Yavapai drive came up blank on my home computer.

What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?

I didn't experience this.

What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.)

The complexity and interrelatedness of living organisms on this planet.

2008-12-12T11:42:00.000-08:00

Compendium Unit 4 Part I

Reproductive System

I. Human Life Cycle

II. Male Reproductive System

III. Female Reproductive System

IV. Female Hormone Levels

V. Control of Reproduction

VI. Sexually Transmitted Diseases

Fetal Development

I. Fertilization

II. Pre-Embryonic and Embryonic Development

III. Fetal Developement

IV. Pregnancy and Birth

V. Development After Birth

Reproductive System

I. Human Life Cycle

The reproductive system in males and females is fully functional once puberty is complete. This occurs between 14-16 in boys and 11-13 in girls. At this time the individual is able to produce procreate.

In males the reproductive organs or genitals produce sperm in the testes and in females eggs are produced in the ovaries. The sperm travels in ducts which exit the penis. In females the eggs in the uterine tube are transported to the uterus. The penis delivers the sperm to the female vagina during intercourse. In the uterus the fertilized egg develops within the females body.

The sex hormones produced by the testes and the ovaries affect the features of masculinization and feminization, and other function such as the continuation of pregnancy.

Cell division occurs in the human life cycle as mitosis and meiosis. Mitosis is duplication division meaning the cells carry the same amount of 46 chromosomes when duplicated. Meiosis is reduction division. The cells divide and have half the chromosomes which means 23. Meiosis takes place in the testes to produce sperm and in ovaries to produce eggs. As the sperm unites with the egg the 23 pairs of chromosomes from the sperm and egg form a zygote that has 46 chromosomes in total.

II. Male Reproductive System

The male reproductive system consists of a pair of testes which are suspended within the scrotum and a network of excretory ducts (epididymis, ductus deferens (vas deferens), and ejaculatory ducts), seminal vesicles, the prostate, the bulbourethral glands, and the penis. Sperm cells pass through the ducts as they leave the testes and move through the urethra.

The epididymis is a tightly coiled tube where the sperm matures and the ductus deferens or vas deferens is where the sperm is stored. The vas deferens curves and empties into the ejaculatory ducts leading to the urethra. The urethra then extends from the urinary bladder to the urethral orifice at the tip of the penis. From this passageway is where sperm and fluids for reproduction and urine from the bladder moves out of the body.

Upon ejaculation sperm leaves the penis in a fluid called semen. Secretions are added from the seminal vesciles, the prostate gland, and the bolbourethral glands. The seminal fluid contains the sugar fructose that is an energy source for sperm.

The male sexual organ the penis is the organ of sexual intercourse. The penis includes the shaft, the glans and the foreskin. In a circumcision the foreskin is removed. The male deposits semen into the vagina during intercourse. The penis contains erectile tissue that engorges with blood during sexual arousal resulting in an erection. As sexual stimulation intensifies rhythmic muscle contractions cause the penis to ejaculate. The expulsion of seminal fluid are part of male orgasm. The sensation is centered in the brain but the physical reactions involve the genitals and entire body.

There can be over 400 million sperm cells in semen that is ejaculated.

The testes which produce sperm and sex hormones lie outside the body within the scrotum. The scrotum regulates the temperature.

Spermatogenesis takes place in the seminiferous tubules. During production spermatogonia divide to produce primary spermatocytes that undergo meiosis I to produce secondary spermatocytes carrying 23 chromosomes. They then undergo meiosis II to produce four spermatids each with 23 chromosomes. The spermatids then become sperm.

Each sperm cell has three parts: a head, middle piece, and tail. An acrosome at the head produces enzymes which helps penetrate the female ovum. Mitochondria in the middle provides energy for movement of the tail. Ejaculated semen contain several hundred million sperm of which only one needs to enter the egg of a female. Andogens or male sex hormones are called interstitial cells because they are secreted by cells between the seminiferous tubules.

III. Female Reproductive System

The organs of the female reproductive system produce and sustain the female sex cells called ova, transport these cells to a site where they may be fertilized by sperm, provide a favorable environment for the developing fetus, move the fetus to the outside at the end of the development period, and produce the female sex hormones. The female reproductive system includes the ovaries, fallopian tubes, uterus, vagina, and external genitals. Ovaries are a pair of sex organs that reside in the pelvis on each side of the uterus. Ovaries produce ova (egg cells) and the sex hormones estrogen and progesterone. The genital tract includes the oviducts, uterus, and fallopian tubes. The oviduct also called fallopian tubes include two tubes which extend from the uterus to the ovaries. At the end of the ovaries is a funnel shaped finger like projection called fimbriae. When an egg bursts from an ovary during ovulation, it moves into an oviduct by the action of the fimbriae and the beating of cilia that lines the oviducts. Once in the oviducts, the egg is moved along by ciliary movement and the peristaltic action of the muscle in the tubes toward the uterus. An egg lives from 6-24 hours. Thus fertilization or zygote formation takes place in the tubes. A developing embryo arrives at the uterus after several days. Implantation occurs when the embryo embeds in the uterine lining.

The uterus is a muscular organ about the size and shape of an inverted pear. It receives the fertilized egg and provides an appropriate environment for the developing fetus. After childbirth, the uterus is usually larger, then gets smaller after menopause. Development of the embryo or fetus normally takes place in the uterus, The womb accomodates for the growing fetus and is able to stretch to the width of 5cm. The lining of the uterus is called the endometrium which is involved in the formation of the placenta. The opening in the cervix leads to the vagina a fibromuscular tube that extends to the outside. The vagina serves as the passageway for menstrual flow, intercourse, and the birth canal during childbirth.

The external genitals are referred to as the vulva. It includes the labia majora, mons pubis, labia minora, and clitoris. The labia minora are two folds that lye inside the labia majora and extend the the vaginal opening to form the clitoris. The clitoris is the organ of sexual arousal in females.

In females, orgasm culminates in uterine and oviduct contractions, however a woman can become pregnant without having an orgasm.

IV. Female Hormone Levels

The hormones estrogen, and progesterone have important roles in the function of the reproductive system. Hormone levels cycle in the female on a monthly basis.

The non pregnant ovarian cycle includes six stages. As the follicle matures, layers of follicle cells surround a secondary oocyte. The mature follicle then ruptures in a process known as ovulation and a secondary oocyte is released. The follicle then becomes the corpus luteum, and eventually disintergrates. During oogenesis, the chromosome number is reduced to 23. The ovarian cycle is controlled by homones. During the first half of the cycle, FSH from the pituitary causes maturation of a follicle that secretes estrogen and progesterone, and after ovulation LH converts the follicle into corpus luteum.

The non pregnant uterine cycle takes place simultaneously with the ovarian cycle. This cycle begins with the follicular phase when FSH is released promoting the maturation of a follicle in the ovary. The ovarian follicle produces increasing levels of estrogen causing the endometrium to rebuild. Ovulation occurs on the 14th day of a 28 day cycle. After ovulation LH promotes the development of the corpus luteum. As a result progesterone is produced by the corpus luteum causing the endometrium to thicken and become secretory and a low level of hormones causes the endometrium to break down as mentruation begins. If pregnany were to occur the corpus luteum does not regress but is maintained and secretes increasing amounts of progesterone, thus menstruation does not occur and the uterine lining is maintained.

V. Control of Reproduction

There are various birth control methods and devices which include birth control pills, diaphragm, and condom. They vary in effectiveness, so the most reliable form is abstinence. Surgical methods include vasectomy in males and tubal litigation in females.

Infertility is the inability of couples to achieve pregnancy. Assisted reproductive technologies include artificial insemination, in vitro fertilization, gamete intrafallopian transfer, surrogate mothers, and intracytoplasmic sperm injection.

VI. Sexually Transmitted Diseases

Sexually transmitted diseases are caused by viruses, bacteria, protists, fungi, and animals. As an example HIV is caused by the human immunodeficiency virus and genital warts by the human papillomavirus, genital herpes by the herpes simplex virus type 2, and hepatitis by the hepatitis virus. Bacteria causes include chlamydia, gonnorrhea, and syphilis. In addition two other bacterial infections include bacterial vaginosis caused by gardnerella vaginalis and trichomoniasis caused by candida albicans.

Fetal Development

I. Fertilization

The first cell of an individual forms upon the union of a sperm and a egg to form a zygote, this is known as fertilization. The zygote contains all the genetic info necessary, including half from the mother and half from the father. As the sperm swims toward and implants in the egg of the female, the head of the sperm containing a nucleus fuses with the egg nucleus. As a result the zygote is formed by the cytoplasm and organelles of only the mother. During fertilization a single sperm first drawn into the egg by microvilli of its plasma membrane. The enzymes from the acrosome help the sperm makes it's way through the zona pellucida. The zona pellucida is surrounded by layers of follicular cells called corona radiata. These cells thus nourish the egg when it is in the follicle of the ovary.

During fertilization, several sperm penetrate the corona radiata,, and several attempt to penetrate the zona apellucida, but only one can enter the egg. After the head of the sperm fuses to the zona pellucida, it releases an enzyme that creates a pathway for the sperm to enter the egg. Polyspermy is the entrance of more than one sperm. This is prevented by the depolarization of the egg's plasma membrane. A s the sperm touches an egg's plasma membrane, it depolarizes from 265 mV to 10mV preventing the binding of other sperm cells. further, the release of enzymes by vescicles called cortical granules cause the zona pellucida to become ad inpenetrable membrane.

II. Pre-Embryonic and Embryonic Development

The processes involved in embryonic development include cleavage, growth, morphogenesis, and differentiation. Cleavage happens immediately after fertilization, as the zygote begins to divide. Increase in size does not occur. Cell division is mitotic as each cell duplicates with a full set of chromomsomes and genes. Growth takes place as the daughter cells grow in size, and morphogenesis occurs as the embryo takes various shapes. As the cells take on specific structures and functions this is known as differentiation.

The development of the embryo in the uterus is accomplished by the functions of the extraembryonic membranes. These include the chorion, allantois, yolk sac, and amnion. The function of the chorion is to provide oxygen, nutrients, and take away wastes. It develps into half of the placenta and the blood vessels within the chorionic villi are contonuous with the umbilical blood vessels. The allantois extends away from the embryo. It accumulates the urine produced by the fetus and the blood vessels become the umbilical blood vessels. The umbilical arteries carry O2 poor blood to the placenta and O2 rich blood to the from the placenta. In humans the yolk sac is the first site of blood cell formation and contains plentiful blood vessels. As in shelled animals with a yolk, the placenta takes on the functions of a yolk. And last, the amnion cushions the embryo as it enlarges and the fluid within insulates it from cold and heat.

The stages of embryonic development include the events that occur from fertilization to birth. The gestation period calculated by adding 280 days to the start of the last menstruation. The period known as pre-embyonic development include the events of the first week. In the first week the zygote divides as it passes from the oviduct to the uterus. This compact ball of embryonic cells called a morula. As the morula further divides the formation of a small cavity appears between cells so there is a inner cell mass surrounded by an outer layer of cells. At this point it is called a blastocyst, however the size has not increased. The inner mass becomes the embryo and the outer becomes the chorion. If the cells of the morula separate, or the inner mass splits and two embryos are present, identical twins with exactly the same chromosomes result. subsequently two different eggs create fraternal twins.

Embryonic development starts from the second week and lasts till the end of the second month. When implantation is successful pregnancy begins. The chorion secretes a hormone that is detected in pregnancy tests called HCG and helps in maintaining the corpus luteum. With progression the inner cell mass becomes the embryonic disk.

Two more extraembryonic membranes form and the amniotic cavity surrounds the embryo as it develops. This event is called gastrulation an example of morphogenesis, as in this case to become tissue layers called the primary germ layers. This process is completed when the disk becomes an embryo with three primary layers; the ectoderm, mesoderm, and endoderm. In the third week the organ systems start to develop and the nervous system is the first to be visible. In the third week the heart begins to form. By the fourth week a body stalk, the future umbilical cord, connects the embryo to the chorion and the fourth extraembryonic membrane, the allantois lies within the body stalk in which it's blood vessels become the umbilical blood vessels and eventually the umbilical cord. In the fifth week limb buds form, the head enlarges, and the sense organs are more visible. The embryo takes on recognizable human features during the six through eighth weeks. With brain development, the head becomes proportional to the the body and a neck develops. Also reflexes along with the nervous system develop. However this all occurs in an embryo the approximate size of an aspirin.

III. Fetal Development

The hormones at this time function to prevent new follicles from developing, and help to maintain the endometrium and the cessation of menstruation. The blood of the fetus and mother do not mix and the carbon dioxide and wastes move from the fetal side to the maternal side, as the nutrients and oxygen move from the maternal side to the fetus by diffusion. At this time, harmful chemicals can cross the placenta. Of particular importance, there are sensitive periods during which an organ or part is susceptible to substances that can alter it's normal function.

The umbilical arteries and vein connect the fetus to the mother. The umbilical vein carrying blood rich nutrients enters the liver, merges and with the inferior vena cava

of the mother. The blood moves to the left atrium, left ventricle, then to the aorta. Oxygen poor blood enters the right atrium and is pumped into the pulmonary trunk, and through the arterial duct it enters the right atrium.

The development of the fetus includes the third through the ninth months of development. In the third month head growth slows and the body begins to increase in size, and external refinements such as fingernails, eyelashes, nipples, eyebrows, and hair appear. Bone is replaced by cartilage in a process called ossification. This process completes about 18 to 20 years of age.

Around the third month the presence of the SRY gene forms either male or female genitals. In the fourth month the heartbeat can be heard through a stethoscope. By the fifth through the seventh month the mother can feel movement. The skin is covered by a down called lanugo and a greasy white substance known as vernix caseosa. The eyelids can now open.

By nine months the fetus is near term. Term babies have the have a better chance of survival compared to premature babies. And the fetus usually rotates it's head toward the cervix in preparation for birth. If the baby does not turn, a breech birth occurs in which a cesarean section is needed for delivery.

IV. Pregnancy and Birth

Hormonal changes can cause fluctuations in energy levels, and the mother may experience fatigue, nausea, vomiting, or loss of appetite. Weight gain occurs due to the mother's own internal changes and the addition of the fetus. Major changes due to placental hormones affect physiological changes. Progesterone relaxes the arteries lowering blood pressure and aldosterone promotes sodium and water retention. Blood volume also increases as cardiac output increases. This increases blood flow to the kidneys, placenta, skin, and breasts.

Changes also occur in pulmonary values, such as a 405 increase in vital capacity and tidal volume. Improvements appear in respiratory functions. Levels of oxygen change slightly but carbon dioxide decrease as much as 20%.

Other affects include compression from the enlarged uterus resulting in bladder incontinence and edema or varicose veins due to decreases in venous return. Also, peptide hormones which induce insulin resistance can induce pregnancy related diabetes.

Childbirth normally occurs at the end of the pregnancy period. Toward the end of this period contractions become more stronger and frequent. Labor is evident when contractions happen every 15-20 minutes and last longer than 40 seconds. the stretching of the cevix can release oxytocin. The contractions in the uterus pushs the fetus downward as the crevix continues to stretch. This process repeats until birth.

There are three stages to birth. In the first stage of contractions the baby's head helps to dilate the cervix and if the amniotic mambrane ruptures the fluid that leaks is known as "breaking water". This stage ends when the cervix is fully dilated. In the second stage the head appears. After the rest of the body emerges the umbilical cord is cut. In the third stage known as afterbirth, the placenta is expelled.

V. Development After Birth

In humans, development continues throughout life. The stages of life include infancy, childhood, adolescence, and adulthood. The latter half of adulthood is characterized by aging. This process of progressive changes can increase the risk of illnesses, disease, and death. The study of gerontology, or aging seeks to increase the health of individuals in their latter years.

References:

http://training.seer.cancer.gov/module_anatomy/unit12_3_repdt_female.html

http://training.seer.cancer.gov/module_anatomy/unit12_2_repdt_male.html

Embryonic and Fetal Development Lab

2008-12-10T14:33:00.000-08:00

Fertilization

Week 1 Fetilization- The sperm and egg join also known as conception. (Not embryonic stage yet)

Week 2 The embryonic disk forms. Gastrulation

Week 3-Early formation of the central nervous system, backbone and spinal column has begun. Major organs are starting to develop.

Week 5-heart begins to beat. The brain has developed into 5 areas and some cranial nerves are visible. Arm and leg buds are visible and the formation of the eyes, lips, and nose has begun. The spinal cord grows.The placenta begins to provide nourishment for the embryo.

Week 7

Week 7-Major organs have all begun to form. The embryo has developed its own blood type, unique from the mother’s. Hair follicles and nipples form and knees and elbows are visible. Facial features are also observable. The eyes have a retina and lens. The major muscle system is developed and the embryo is able to move.

Week 8- The embryo is reactive to its environment inside the amniotic sac where it swims and moves. Hands and feet can be seen. At the end of week 8, the embryonic period is over and the fetal stage begins.

Week 13-16

The brain is fully developed and the fetus can suck, swallow, and make irregular breathing sounds. Eyebrows and eyelashes appear and the fetus makes active movements including kicks and even some somersaults.

Week 20-“Quickening” (when the mother can feel the fetus moving) usually occurs around this time. Finger and toenails appear. Lanugo, a fine hair now covers the entire body. The fetus can hear and recognize the mother’s voice. Sex organs are visible on ultrasound devices.

week 25-28

Rapid brain development occurs during this period and the nervous system is able to control some bodily functions. The fetus’ eyelids now open and close. At 25 weeks there is a 60% chance of survival if born. The fetus is considered legally viable at 28 weeks and there is a 90% chance of survival if born at this point.

Term Pregnancy

Week 36-37

Most babies will be in a head down position at this point. However, about 4% of the babies will be breech.

Pregnancy is considered a "term" pregnancy at this point and nothing will be done to stop labor in most circumstances. You should plan to take a tour of your birth facility if you have not previously. If you are having a home birth try to invite everyone over for a quick run through of what you expect.

2008-12-09T13:50:00.000-08:00

Compendium Unit IV-Part II

Human Evolution

I. Origin of Life

II. Biological Evolution

III. Classification of Humans

IV. Evolution of Hominoids

V. Evolution of Humans

Global Ecology and Human Inferences

I. The Nature of Ecosystems

II. Energy Flow

III. Global Biochemical Cycles

Human Population, Planetary Resources, and Conservation

I. Human Population Growth

II. Human Use of Resources and Pollution

III. Biodiversity

IV. Working Toward a Sustainable Society

Human Evolution

I. Origin of Life

Deep time evolutionary history stretches back billions of years. It is only within the past several millions of years that human like life forms appeared. The earliest forms of life found by carbon dating appeared around 3.8 billion years ago. As oxygen levels rose due to photosynthetic activity new life forms evolved. Use of carbon by life forms to make energy releasing oxygen lead to the appearance of complex cells. The presence of molecules of life leads to presence of glucose, fatty acids, amino acids, nucleotides, and purines.

The earth was formed of dust particles and debris some 10 billion years ago. Theory suggests that humans evolved from nonliving chemicals which reacted to form the first cells. This happened because the gravitational pull of the earth prevented gases in the atmosphere from escaping into space. Volcanic gases in the atmosphere at that time included nitrogen, carbon dioxide, hydrogen, and carbon monoxide, but oxygen did not exist in yet.

After some time the earth began to cool and the condensation of water vapor turned to rain. From these water vapors trapped in the atmosphere heavy rains ensued for hundreds of millions of years, eventually forming the earth's oceans

Further along, other gases mixed with the oceans creating neucleotides and amino acids, organic compounds formed by the reactions of available energy such as volcanoes, meteorites, radioactive isotopes, lightning, and ultraviolet radiation.

To test these theories, the reactions were simulated in 1953 by Stanley Miller using an apparatus resembling a closed system. Gases present in the early earth model were placed in the system and heated. As the gases cooled it produced a variety of small organic molecules, as was theorized. It is thought that small organic molecules joined to produce organic macromolecules.

Two theories are hypothesized in the next step of evolutionary process. The RNA-first hypothesis states that one macromolecule RNA created the first cell.

Because amino acids join when exposed to heat, the protein-first hypothesis suggests that amino acids that pooled in shallow areas eventually were exposed to sunlight creating proteinoids, small polypeptides. As the proteinoids were reintroduced to water, they formed microshperes, which have many of the cell properties.

It was further found that if a lipid is joined with a microsphere, a liquid protein membrane forms. Thus, a protocell could have formed. A protocell can carry on the functions of metabolism, but is unable to reproduce. An environment of plentiful small organic molecules in the ocean could have provided food for the cells. These cells were most likely fermenters since oxygen did not exist in the atmosphere at that time. It is supposed that these cells were heterotrophs.

The next question is how did the cells replicate? The replication of DNA is necessary for cell reproduction to occur. Enzymatic proteins are also required in cell divsion. Two theories were derive in order to answer this question. The RNA-first hypothesis suggests that the RNA genes could have specified protein synthesis, with some of the proteins resulting in forming enzymes. If the enzymes carried reverse transciptase it could possibly have served as a RNA template to forming DNA leading to the process of DNA replication. However, the protein-first hypothesis postulates that enzymatic synthesis evolved within the protocell, enabling DNA to synthesize from nucleotides in the ocean. Once in place, the DNA could then specify protein synthesis thus obtaining all the needed enzymes to replicate DNA.

II. Biological Evolution

All living organisms today can be traced to the simplest cell forms. Some of the first cells (unicellular) without a nucleus are called prokaryotic cells. Cells evolved to having a nucleus are called eukaryotic cells. From these basic cell forms multicellularity emerged. Further along, life forms evolved such as fishes, then plants and animals.

There are two aspects important to the process of biological evolution. They are descent from a common ancestor and adaptation to the environment. Tracing all living things back, we realize all living things share the same chemistry and cellular structure. Adaptation accounts for the diversity in living things resulting from survival in different conditions.

The theory of evolution was formulated by Charles Darwin, an English naturalist. During his travels he documented the diversity of life forms. Based on fossil remains, anatomical and biogeographical characteristics he surmised that life forms changed over time.

Today fossil remains are still being studied as it provides some of the best evidence for evolution. Fossils are most commonly found in sedimentary rock. Sediments provide recognizable layers that develop over time giving paleontologist a way of dating the remains. A process called mineralization preserves the bony parts of life forms. The fossils and data gathered by paleontologists create a fossil record shaping the history of life, ancient climates, and environments. A substantial amount of data has been acquired to form the branch of science called paleontology.

As previously mentioned, all life evolved from simple to complex forms. Nonflowering plants existed before flowering plants, and amphibians existed before reptiles and dinosaurs. Dinosaurs are directly linked to birds and indirectly linked to mammals.

Fossil remains of species that have the characteristics of two differing groups are called transitional fossils. These fossils are important to determining how evolution occured. One such example is the ambulocetus natans, a walking whale that swims. It was long thought that whale evolved from land creatures.

Other measures used to support the theory are biogeographical evidence, anatomical evidence, and biochemical evidence. Biographical evidence suggests that life forms evolved from a particular environment and then spread from there. This distribution of plants and animals to different places throughout the world explains why unique species can be found in isolated areas. There are many species of finch in the Galapagos. To explain this, the finch migrated from the mainland and in isolation and adaptation evolved into a different species.

Anatomical evidence suggests common ancestry among organisms that share similar anatomical characteristics. Similarity in structure known as homologous structures indicates a shared common descent. For example, horses, humans, whales, and cats have similar forelimbs. Yet, these limbs perform different functions. Different structures that perform the same function are called analogous structures and do not share common ancestry. Another anatomical characteristic that supports evidence of evolution are vestigial structures. In some animals the presence of bone structures that seemingly provide no function such as the pelvic girdle in whales and the tail bone in humans give clues to the evolutionary process of the organisms ancestry. It is thought the the anatomical structures provided a function in earlier species. Also, in embryonic stages, vertebrates share common characteristics although they mature into different life forms.

Common to most life forms are the similar use of biochemical molecules including DNA, ATP, and various enzymes. Genetic and biochemical evidence supports the idea that humans share a large number of genes with simpler organisms and that diversity exists by a slight difference in the regulation of genes. A way of determining common descent is in examining the DNA base sequences and amino acid sequences of proteins for similarities.

Natural selection supports the evolutionary theory of species. Of an existing species, the traits that are better suited for survival are naturally selected in subsequent generations to ensure survival through adaptation. Thus this process is called natural selection. For example, among a group of giraffe, the one's with a longer neck where able to forage for food that perhaps were out of reach for the shorter necked giraffe, thus this increased it survival potential. Traits that aren't beneficial become less common. Natural selection results from variation, competition for limited resources, and adaptation.

III. Classification of Humans

The classification of organisms is derived from the relatedness of evolutionary descent. An organisms binomial name gives it's genus and species. Within the same domain organisms share only one general characteristic, but those in the same genus have more specific common characteristics. From classification we are able to determine a organisms evolutionary relationship. A diagram similar to a family tree depicts the evolutionary path of an organism. As different branches form representing new life forms, the ones that share the branches closest to the trunk are more closely related. Through the use of DNA research and the study of rRNA sequences scientists determined of the three domain system of classification including bacteria, archaea, and eukarya, humans are more closely related to fungi than to plants.

Humans are primates of the anthropoid suborder. Primates have two suborders. The prosimians include lemurs,tarsiers, and lorises and the anthropoids are another, including monkeys, apes, and humans. Some similarities we share among primates are mobile limbs for grasping and five fingers and toes. Depth perception in vision is also another trait we share. Apes and humans are able to see green, blues, and reds because we have three different cone cells. Human have complex brains which evolved to be larger in size. The expansion of the cerebral cortex grew larger as more complex visual and coordination skills increased. Single births are the norm for primates.

Chimpanzee and humans genomes are 99% identical. The 1% resulting in speech, hearing, smell, and anatomical differences. Humans are structured to walk upright and chimpanzee rest on their knuckles.

IV. Evolution of Hominoids

It is was once thought that humans evolved from apes. Fossil records now tell us that apes and humans shared a common ancestor about 7 million years ago. This being so, we are then distant cousin's having evolved as contemporaries.

The first hominoid of fossil records has not been determined. To determine the divergence of a lineage, at first genes and proteins are nearly identical but as time passes each lineage acquires genetic changes. With molecular data genetic changes give clues to the relatedness of the two groups and possibly the time of divergence.

Anatomical features are used to determine if a fossil is hominoid. One feature is bipedal posture referring to an upright stance. The other is facial features. Human's have a flatter face, more noticeable chin, a shorter jaw, and smaller teeth than apes. The third is brain size. Consequently, the bipedal posture is the most prominent feature.

The earliest fossils of hominoids date back to 7 mya when the ape and human lineages split. it is known that the hominoid line began with the australopithecines, a species that evolved and diversified in Africa. This species was first discovered in southern Africa in the 1920's. It walked upright and lived around 1.5 mya to 2.8 mya. In eastern Africa a hominoid called A. afarensis was discovered more than 20 years ago. It stood upright and walked bipedally, although it's brain was small. Because it was more ape like above the waist and more human like below the waist the evolutionary process that accounts for different parts changing at different rates is called mosaic evolution.

V. Evolution of Humans

To classify a fossil to the genus Homo there are three criteria. First the brain must be 600cm3 or greater, and secondly the jaw and teeth must resemble those of humans. Lastly, there must be evidence of tool use.

The early Homo habilis lived between 2.0 and 1.9 mya and were possibly the ancestors to humans. They had a brain size of 775 cm3 and had smaller cheek teeth, therefore it is likely that they were omnivores who ate plants as well as meats. These hominoids also used tools to cut or scape meat and bones. their skulls showed enlarged portions of the brain related to speech. From this it is thought that this ability to speak led to hunting and gathering cooperatively. As a result society and culture could have began. It is further speculated that the formation of culture could have hastened the extinction of the australopithecines.

Another species the Homo erectus dated back to 1.9 mya and 0.3 mya. These fossil remains were found in Africa, Asia, and Europe. It is known that this species was the first to use fire and more advanced tools.

Homo floresiensis was discovered in Bali in 2003 and might have became extinct 12,000 years ago due to a volcanic eruption. Interestingly they are small with brain sizes one-third that of human's. Further research is continuing to understand this species unique characteristics.

Homo sapiens the name for modern humans, evolved from Homo erectus. The hypothesis that Homo sapiens evolved in several different locations is called multi regional continuity hypothesis. Opposition to this theory state that different places would have produced genetic variations. Instead, they hypothesized that Homo sapiens evolved from Homo erectus in Africa and within the past 100,000 years migrated elsewhere suggesting that humans are more genetically similar. Most recent studies tend to support the out-of-Africa hypothesis.

Neandertals date back to 200,000 years BP. They were inhabitants of Europe and Asia during the last Ice Age. In accordance with the out-of-Africa theory they were replaced by modern humans. Their brain was slightly larger than ours and evidence suggests that they were culturally advanced. They used tools and perhaps built homes. The use of fire for cooking and warmth is also evident. Also, they buried their dead and were capable of thinking symbolically.

Cro-magnons are most similar to modern humans and possibly entered Europe and Asia 100,000 BP or earlier. Cro-magnons might have replaced Neandertals in Middle East before spreading to Europe. They also produced tools and might have been the first to use language. Their culture included art found on the cave walls in Spain and France.

Lastly, current variations among people of different locale is known as ethnicities. It is found that genotypes of different modern populations are extremely similar. Protien and DNA sequences show a common ancestor within the last 1 million years. There is little anatomical and biochemical differences among population.

Global Ecology and Human Inferences

I. The Nature of Ecosystems

In a community the interactions among species can be beneficial, damaging, or neutral. This co-evolving can take the form of: benefitting both species (symbiotic), benefitting one species without harm to the other (commensal), the use of one species of another where both benefit in the long term (mutualism), when one species is the host and the other the parasite (parasitic), and/or when one species is the prey and the other the predator (predatory).

The ecosystem encompasses the entirety of physical and chemical interactions among organisms in a biosphere. Among these the human ecosystem is one of the most complex. It encompasses social, cultural, political, and biophysical relationships. The biosphere is maintained by the entirety of these interactions.

Different geographical locations produce several distinct terrestrial ecosystems called biomes which are classified by temperature and rainfall. Deserts vary in temperature and do not have much rainfall. Tropical rain forests have moderate temperatures and plenty of rainfall and tropical grasslands are hot with moderate rainfall. Temperate grassland or prairies have low to high temperatures and not much rainfall. The taiga receives moderate rainfall and low temperatures. And the tundra has the lowest temperatures with moderate rainfall.

The major aquatic systems are subdivided by into freshwater and saltwater. Marine ecosystems comprise of 70% of the earth's waters. Marine ecosystems near the coast have the richest ecosystems.

The components of an ecosystem are made up of abiotic, non-living things and biotic, which are living things. Biotics are autotrophs or heterotrophs. Autotrophs are considered producers since they need inorganic nutrients and an outside energy source to produce organic nutrients. Photosynthetic oraganisms like algae produce organic nutrients for the biosphere. Needing an organic source of nutrients hetetrophs are consumers. An example of hetetrophs ae herbivores, carnivores, and omnivores. Herbivores feed only on plants or algae. Carnivores consume other animals, and omnivores feed on both animals and plants.

Other organisms feed on decomposing particles or matter. Decomposers known as detritus feeders are valuable since they are able to release inorganic substances that are taken up by plants. For instance, fungi, mushrooms, and bacteria get nutrients by breaking down organic matter and release inorganic substances back into the ecosystem.

II. Energy Flow

An important aspect of the interactions within an ecosystem is energy flow and chemical cycling. Energy flow refers to the continual flow of absorption of solar energy via photosynthesis to produce organic nutrients for themselves or others in an ecosystem. Chemical cycling occurs when inorganic nutrients are returned to the producers from the atmosphere or soil. As nutrients pass from one population to another much of the energy used for cellular respiration is dissipated as heat into the environment. The wastes and death of an organism become the nutrients for decomposers. Decomposers convert organic nutrients into inorganic chemicals which are released into the atmosphere or soil. The inorganic chemicals are then absorbed by the producers which perpetuates the cycle.

To illustrate the interconnectedness of organisms energy flow can be depicted in a food web diagram. A diagram the describes the feeding relationships of organisms. The grazing food webs shows the connection of vegetation eaten by herbivores that in turn become food for carnivores. The detrital food webs start with the decomposers and can also be eaten by carnivores so these two webs are also interlinked.

A food chain shows a single path of which animal eats which. It can be depicted as a straight line, whereas a food web shows the relationships of how plants and animals are connected. A food chain shows a path of which an animal finds food.

Trophic levels describe the position that an organism occupies in a food chain. This means all the organisms that feed at a particular link in the food chain. Thus, the first level are primary consumers, the second level are secondary consumers, and so forth. As described previously, every time there is an exchange of energy between one level and another, there is a significant loss of energy. A pyramid best displays this dynamic. For example grass would be at the bottom and a mountain lion would be at the top. Each level implies a loss of energy and efficiency. The pyramid model does not portray factors such as changes in reproduction and consumption.

III. Global Biochemical Cycles

Biochemical cycles represent the pathways which chemicals circulate which involve biotic and nonliving geological components. There are two cycles, gaseous and sedimentary. In a gaseous cycle, as in carbon and nitrogen, the element returns to and is withdrawn from the atmosphere as a gas. In a sedimentary cycle or phosphorus cycle, chemical is absorbed from the soil by plant roots, then passed to heterotrophs, and eventually returned to the soil by decomposers.

Pollution in the environment can result from human activities such as industry and mining since it changes the balance of nutrients in the environment.

The Water Cycle- refers to the transfer rate of water in an ecosystem. This cycle is created by evaporations from bodies of water, land, and plants, followed by condensation and rainfall back to streams, oceans or land.

The Carbon Cycle- is a complex cycle involving the exchange of carbon in the atmosphere, terrestrial biosphere, oceans, and sediments. Carbon dioxide in the atmosphere is utilized by producers and converted to organic molecules used to feed other organisms. The burning of fossil fuels by humans greatly impacts the environment. Global warming is the result of the increase greenhouse gases, trapped COs. Imbalances can cause changes in sea level and weather due to warming effects.

The Nitrogen Cycle- is important to plants. It is not directly used by plants and is a nutrient that limits the amount of growth in an ecosystem. Nitrogen is plentiful in the air and through the actions of bacteria and algae become a part of biological matter. Bacteria in aquatic systems and in the soil are able to convert nitrogen to ammonium. This process is called nitogen fixation. Some plants form nodules on the roots where nitrogen fixation takes place converting nitrogen to ammonium which is used by plants. Plants also use nitrates and and it's production during the cycle is called nitrification. Soil bacteria converts ammonium back to nitrites, and nitrate producing bacteria convert nitrites to nitrates. to complete the cycle nitrate is converted to nitrogen gas by dentrifying bacteria in lakes, bogs, and estuaries. This means that dentrification counterbalances nitrogen fixation.

Fertilizers used by humans significantly the balance in such ways such as run off.

The Phosphorus Cycle- reservoir is ocean sediments. Phosphate is also a limiting nutrient in ecosystems. It is made available by the exposure of sedimentary rock through geological upheaval or natural weathering of rocks. In soil, plants use phosphate in molecules for ATP and nucleotides that become part of DNA and RNA. Animals that feed on producers take in phosphate for teeth and bones. Upon death phosphate ions are once again recycled.

Cultural eutrophication the overenrichment of waterways is created by excess amounts of nitrogen and phosphates from runoffs of fertilizer and detergents. Other hazards that impact the ecosystem are disease causing agents, pesticides, industrial chemicals, heavy metals, and radioactive substances. Biological magnification refers to the process whereby increased concentrations of these hazardous substances are absorbed along the food chain in organisms because it sits in the body.

Human Population, Planetary Resources, and Conservation

I. Human Population Growth

Humans are the largest population of large mammals on earth. Strong human intervention is present in almost every part of our planet. Population growth is one factor that impacts our environment.

Human population growth continued to rise steadily after 1750 and in the 1950's took a steep upward increase followed by exponential growth. It peaked around 1990 with an annual growth of 87 million. To determine growth rates we take the number of those born in a year and subtract the the number of those who died within the year. Growth rate is affected by conditions. Ideal conditions create growth and diminished food and space can cause decline. The population levels off when carrying capacity is reached. Currently this capacity has not been determined.

The living standards of the worlds population can be defined in two groups. More developed countries (MDC) and less developed countries (LDC). At present the MDC's are actually decreasing in size. On the other hand the population in the US is continuing to grow at .6% because of immigration and a high percentage of women still of reproductive age.

In contrast LDC's are seeing increases in growth rate due to better healthcare, reducing mortality, and increased birthrates. Future population is expected to increase in Africa and Asia. Water scarcity, loss of biodiversity, and pollution are growing concerns in Asia because 56% of the world's population inhabit the locale.

The use of age structure diagrams illustrate the momentum of population growth. These diagrams show future growth by assessed the number of persons in preproductive, reproductive, or postproductive stages.

II. Human Use of Resources and Pollution

There are five resources widely used and important to humans. These include land, water, food, energy, and minerals. All living things affect the ecosystem. Our lifestyle and how we use our resources, that is the amount one consumes and the amount of waste a person produces defines one's ecological footprint. How we determine the use of these resources will reflect our co-evolution within our ecosystem. Humans utilize nonrenewable and renewable resources. Nonrenewable resources are slow to replenish and through extensive use can run out. Renewable resources are considered more abundant or capable of replenishing naturally.

Land is needed for agriculture, homes and civilizations needs. The diversity of land include beaches, deserts, and rainforests. Human activities alter landscapes by habitation, leading to erosion, deforestation, and desertification.

Water is essential to life on earth. Seventy percent of the world's freshwater is used for agriculture. In some areas water use exceeds the renewable supply. Depletion of groundwater and aquifers are a growing concern around the world. Methods for conserving water are often encouraged on the local level. Some ways to conserve involve planting drought tolerant plant species especially in arid climates. Using drip irrigation and incorporating systems that reuse water.

Food is a resource sustained by agriculture, livestock and fishing. Modern methods of agriculture has yielded larger food supplies. Unfortunately, some methods have also produced detrimental effects such as pollution from pesticides and fertilizer, monoculture, drain on water supply, and heavy fuel consumption. We affect natural selection by the crops we choose to grow. Domestication of species is the result of our co-evolving relationship with our biological and physical landscape. Genetically engineered crops have been produced in hopes of larger yields and resistance to cold and pests. Raising livestock requires more energy to produce than other foods. Raising livestock requires fossil fuel, water, fertilizer, and nearby waterways are greatly affected by runoff of wastes.

Energy is used for transportation, heating homes, etc. We use renewable and nonrenewable sources. Fossil fuels are considered nonrenewable and contribute to greenhouse effects. Renewable resources include hydropower, geothermal, wind, and solar.

Minerals are another resource that is widely used for commercial and industrial use. The extraction of minerals from the earth and causes erosion, loss of vegetation, and toxic runoff. This resource is nonrenewable and include, ore, diamonds, uranium, etc. Other health hazards and concerns include the build up of organic chemicals and solid wastes because there is limited land and water to dispose of these materials.

III. Biodiversity

Biodiversity accounts for the variety of life forms on earth. It represents the various species of plants, animals, and microorganisms, and the diversity of genes within a species. The various ecosystems on this planet such as deserts, rainforests, coral reefs, and savannas are all part of a biologically diverse earth. A diversity of species ensures recovery and prevention promoting balance in a ecosystem. From nature we derive medicines to treat illnesses and disease. We also grow plants and vegetable for consumption. Our choice of agriculture and methods have a direct affect on our ecosystem. Thus, many factors indirectly influence our environment. The ability of an ecosystem to recycle waste, water, and the balance of biochemical cycles are all important to preventing the deterioration and extinction of species.

IV. Working Toward a Sustainable Society

Conservation and sustainable development strategies attempt to address habitat loss, pollution, the impact of non native species, exploitation, and disease. Sustainable development and consumption helps to avert ecological problems. Management of resources and awareness of preservation helps to insure the viability of future generations. To achieve this change, renewable energy and recycling is encouraged.

Sustainability is also determined by our relationship to food and other resources. This relationship directly and indirectly affects our quality of life. Thus, how we co-evolve is dependent on our domesticate relationships with our physical and biological landscape.

References:

http://www.elmhurst.edu/~chm/onlcourse/chm110/outlines/nitrogencycle.htmlhttp://en.wikipedia.org/wiki/Trophic_level

http://www.globalissues.org/issue/169/biodiversity

http://www.sciencebob.com/lab/q-web-chain.html

http://en.wikipedia.org/wiki/Carbon_cycle

http://en.wikipedia.org/wiki/Human_evolution

2008-12-08T13:08:00.000-08:00

Human Landscapes Ecology Lab

2008-12-06T21:27:00.001-08:00

Human Landscape Ecology Lab

Objective: To determine how demographics and characteristics affects the future growth of an area or country.

What was your high fertility rate country and what was it's fertility rate?

The country I chose that has a high fertility rate is India. Their fertility rate is 3.75.

What was your low fertility rate country and what was it's fertility rate?

The country I chose that has a low fertility rate is Italy. Their fertility rate is 1.6.

The initial demographic "shape" of your high fertility rate country should have been a pyramid, with high population in young age groups. Explain why high fertility rate results in a high percentage of young people in the population. How does this affect future population growth?

The pyramid indicates that population toward the base is larger and representative of a younger age group. This means that a large percentage of the population will eventually be approaching child rearing age which will create an increase in population. Because of this if factors remain relatively the same growth will continue.

Your low fertility rate country might have a more oval-shaped curve with a high population in middle age groups. This is especially exaggerated if the fertility rate is below 2.00. Explain why low fertility rate leads to lots of middle aged people.

The oval shape shows that there are fewer young people and more middle aged people in the population. Within this population the persons approaching their reproductive years are fewer and the majority of the population leaving their reproductive years are on the increase.

Write ten adjectives or descriptive phrases for what you might expect life, people's attitudes, conditions on the streets, etc. will be like in each of those situations. Imagine a situation with lots of middle-ageded and older people in the population and write ten quick "brain-storm" descriptors for you think it would be like. Then do the same for a situation with lots of children in the population.

Scenario:Large population of middle-older aged people

Looking to down-size

Concerned about retirement

Seeking less strenuous physical activity

Less shopping

Schools and activity centers geared toward mature activities

Television programming for maintaining health

More programs at hospitals for age related diseases

More retirement based communities

Movies reflect age issues

Less busy

Scenario: Large population of children in the population

Busy mornings in the home and in the streets

Lots of shopping to keep the children fed and dressed

Adults are concerned about needing larger living space.

More use in parks and playgrounds.

Middle aged adults gather around children's activities

Schools at full capacity

More games and toys and children's shows on television

Lots of traffic around schools in the morning and after school

Sharing ideas about raising children

House work and chores, lots of laundry

2008-12-05T14:29:00.000-08:00

2008-12-05T14:14:00.000-08:00

Unit 4 Lab- List of Species

2008-12-05T14:05:00.000-08:00

Objective: Within our human landscape list species we have co-evolved with and how we interact with them.

Hummingbird-Selasphorus sasin-Symbiotic- they help in pollination and we sometimes put out feeders, fun to watch-wild

Mosquito-Culex tarsalis-Parasitic, they suck blood and can spread viruses-wild

Chicken-Gallus domesticas-Mutualistic- they are a food source and as livestock we feed and tend to them-domesticated

Onion-Allium sepa-Mutualistic- An agricultural crop-domesticated

Garlic-Allium sativum-Mutualistic- An agricultural crop-domesticated

Sweet Potatoes- Ipomoea batatas-An agricultural crop-domesticated

Agave Plant-Agave americana-Commensal-Is planted and is also abundant in this area-wild/domesticated

Carrots- Daucus carota-Mutualistic-Is an agricultural crop-domesticated

Juniper Berries-Juniperus sabina-Commensal- Provides shade and berries can be used for gin or medicinal uses. Native to the area-wild

Mulberry Tree-Broussonetia papyrifera-Commensal- Provides shade and puts out oxygen-must have been planted but doesn't require watering-domesticated

Crape Myrtle-Lagerstroemia indica-Mutuaslistic-Most likely planted,decorative,needs some watering-domesticated

Coyote-Canis latrans say-Commensal-Scavenger that rabbits from overpopulating-wild

Mountain Lion-Felis concolor linnaeus-Predator- Keeps certain animals in the wild from overpopulating-wild

Red Tailed Hawk- Buteo jamaicensis-Commensal-Keeps pests from overpopulating-wild

Turkey Vulture- Carthartes aura-Commensal-Micruroides Euryxanthus Kennicott-Commensal-Is a scavenger, keeps pests from overpopulating-wild

Coral Snake-Micruroides euryxanthus kennicott-Commensal-Keeps insects from overpopulating-wild

Coral Snake-Micruroides euryxanthus kennicott-Symbiotic-If kept as a pet-domesticated

Bald Eagle-Hailaeetus leucocephalus-Commensal-Keeps the pest population in balance-wild

Dog-Canus lupus familiaris-Symbiotic-Provides companionship and in return is taken care of-domesticated

Cat-Felis catus-Symbiotic-Provides companionship and in return is taken care of-domesticated

Horse-Equus caballus-Symbiotic/Mutualistic-Provides companionship or can be used for work-domesticated

Cattle-Bos taurus-Mutualistic-Is livestock we tend-domesticated

Honeybee-Apis mellifera-Mutualistic-For food we tend the colonies-domesticated

Cow-Heracleum lanatum-Mutualistic-Is livestock we tend-domesticated

Rose Bush-Rosa indica-Mutualistic-Decorative or used for infusions. We water and maintain plant-domesticated or can be wild

Bitter Melon-Momordica charantia-Mutualistic-Grown as food, also has medicinal qualities-domesticated

Reishi-Ganoderma lucidum-Commensal-Food with medicinal qualities-domesticated or wild

Ice Man Polypore-Piptoporus betulinus-Commensal-Food with medicinal qualities-domesticated or wild

Intestinal Flora-Lactobacillus acidophilus-Mutualistic/Symbiotic-benefits the health of the intestines-domesticated

Tooth Plaque-Streptococcus mutans-Parasitic,we are the host/ leads to tooth decay-domesticated

Cotton-Gossypium-Mutualistic-An agricultural crop used for clothing, textiles, and paper-domesticated

Compendium Topic Two

2008-11-14T21:41:00.000-08:00

Skeletal and Muscular System

I. Skeletal System

Function and Anatomy

Bone Growth, Remodeling and Repair

Bones of the Axial Skeleton

Bones of the Appendicular Skeleton

Articulations

II. Muscular System

Types and Function

Skeletal muscle Fiber Contraction

Whole Muscle Contraction

Muscular Disorder

Homeostasis

I. SKELETAL SYSTEM

The skeletal system provides the shape and form for our bodies. It is also important in supporting, protecting, facilitating movement, producing blood for the body, and storing minerals and fat. Bone, cartilage, and fibrous tissue make up this framework.

Function and Anatomy

It's 206 bones form the basic frame from which soft tissue and organs are attached. As we stand the skeleton supports the body from the legs up. Support comes from the legs bones, to the pelvic girdle, and through the abdominal cavity. The organs in the body are protected by the skeleton. The spinal cord is protected by the vertebrae, the brain by the skull, and the heart and lungs by the rib cage and sternum. Blood cells are produced in the bone marrow. Bones sore minerals such as calcium and phosphorous, and fat is stored in the yellow marrow.

The long bone is encased by periosteum a connective tissue layer containing blood vessels, lymphatic vessels, and nerves. The length of the bone, the main portion called the diaphysis has a large medullary cavity filled with yellow marrow. The widened areas at the end of the bone are epiphysis, spongy bone containing red bone marrow. It is covered by hyaline cartilage. This is where red bone marrow is made. Along it's length long bone is composed of compact bone. It is made of organized tubular units known as osteocytes. Osteocytes exchange nutrients and wastes with the blood vessels.

Softer than bone cartilage is gel like and contains no blood vessels and nerves. There are three types. Hyaline is found at the ends of long bones, in the nose, ribs, larynx and trachea, and is firm and flexible. In the knees and vertebrae fibrocartilage provides support. Elastic cartilage is the most flexible located in the ear flaps.

The ligaments that connect bone to bone are made of fibrous connective tissue and are also called articulations.

Bone Growth, Remodeling, and Repair

The growth of bone starts at about six weeks and can last till 25. However it can continue to change due to factors of external stress. It's change in shape, size and strength is called remodeling. Different cells are involved in growth, remodeling, and repair. Osteoblasts are bone forming cells and osteocytes are mature bone cells derived from osteoblasts. Osteoclasts break down bone assisting in depositing calcium and phosphate to the blood.

There are two forms of ossification, formation of bone. In Intramembraneous ossification bones develop between sheets of fibroooous connective tissue. Endochondral ossification replaces cartilage with bone. This is how most of the bones are formed. The stages of ossification change cartilage to bone, then spongy bone is created by osteoblasts further creating the medullary cavity. As the bone lengthens so does the diameter. Once the epiphyseal plates close growth stops.

Specific hormones are important to the growth of bone. Vitamin D is converted to a hormone in the intestinal tract and is important to the absorption of calcium and growth hormone is essential for overall growth.

The functioning of bone remodeling also promotes homeostasis. The renewal of bone lets the body regulate the amount of calcium in the blood. This is also accomplished by specific hormones. Remodeling happens because osteoblasts form bone and osteoclasts break down bone.

Bone repair is similar to bone growth except in it's first stage. There are four stages. Hematoma, the place of injury where blood clots. Fibrocartilaginous callus then fills the space which eventually becomes bony callus. And the last stage remodeling occurs when new compact bone is built.

Bones of the Axial Skeleton

The axial skeleton lie in the mid- line of the body. These include the skull, hyoid bone, vertebral column, and the rib cage. The skull is made of eight cranial and fourteen facial bones. Cranial bones protect the brain and they are easy to remember because the major bones bones share the same names as the lobes of the brain. The frontal, parietal, occipital and foramen magnum where the spinal cord joins the base of the skull. Below the parietal bone lies the temporal bone and the sphenoid bone spans the cranium behind the eye sockets. The facial bones consist of the two jaw bones, the mandable and maxillae, the zygomatic bones of the cheekbone, and the nasal bones.

Within the larynx sits the hyoid bone. It' s purpose is to secure the tongue and is involved in the muscle that allow swallowing.

The vertebral column protects and houses the spinal column. It consists of 33 vertebrae named according to their location and has 4 curvatures to provide resilience and strength. Fibrocartilage can be found between the disks. The cartilage cushions the spine to reduce friction caused by movement.

The rib cage or thoracic cage consists of 12 thoracic vertebrae and 12 pairs of ribs. The upper seven pairs connect to the sternum. The cartilage connecting the ribs to the sternum expand and contract as the lungs breathe.

Bones of the Appendicular Skeleton

The appendicular skeleton are the appendages that attach to the axial skeleton. It consists of 126 bones functioning to produce movement. The pectoral girdle and upper limb produce flexibility and the lower pelvic girdle and lower limbs stabilize the body and are the strongest bones in the body. For each part there is a left side and a right side.

Articulations

Where bones meet it forms a joint. there are three types. Fibrous joints cannot move such as in the cranium. Cartilaginous joints in the ribs move slightly and synovial joints are filled with synovial fluid which enables it to move freely. Sacs called bursae cushion bone and muscle movement.

II. MUSCULAR SYSTEM

The human body contains more than 650 muscles which attached to the skeleton which provides us with movement. Each muscle fiber has several nuclei. Skeletal muscle can make up 40% of an adults body weight.

Types and Function

All muscles are able to contract. There are three types of muscle. Smooth muscle is involuntary and has striations and are found in the walls of organs and veins. The heart walls contain cardiac muscle that is striated. Intercalated disks in the membrane have gaps to enable the heart to contract and relax. Skeletal muscle attach to the skeleton made of bundles of muscle fibers and are voluntary. They function to support posture and provide movement. Contraction of the muscle produces heat caused by ATP breakdown, and the pressure created by contraction keep the blood and lymph moving. The muscles also protect the organs as well. The contraction of these muscles at death is called rigor mortis. Whole muscles are made up of bundles of muscle fibers called fascicles. These muscle fibers are surrounded by connective tissue that extends beyond the muscle creating tendons. Skeletal muscles operate in pairs and the nervous system stimulates the group of muscles to provide the right balance of movement.. Thus one muscle that is performing the most work is called the prime mover and the supporting muscles are called the synergists. An example of this is the biceps brachii and the triceps brachii.

Skeletal muscle Fiber Contraction

The striated features of skeletal muscle represent the arrangement of myofilaments in the muscle fiber. There are special names for the cell components in muscle fiber. The plasma membrane is called the sarcolemma, the cytoplasma is sarcoplasma, and the endoplasmic reticulm is the sarcoplasmic reticulum. A unique feature to the the cell is it's T-tubules that dip into the cell. The expanded areas of the reticulum are calcium storage sites important to muscle contraction. The sarcoplasmic reticulum contains hundreds to thousands of myofibrils, and interestingly contains glycogen and myoglobin. The units of myofibrils make up sacromeres that contain myosinand actin. The filaments act in different ways. Thick filaments are made of myosin and contain myosin heads. The thin filaments are made up of intertwined strands of actin and troponin and tropomyosin. Muscle contraction is created when when the sacromere shortens due to the sliding effect of the actin and myosin filaments.

Nerve impulses carried by motor neurons can stimulate several muscle fibers because of it's branched ends. Between the axon terminal and a muscle fiber there is a gap called the synaptic cleft. When the impulse arrives at the axon terminal neurotransmitters are released and diffuses binding to receptors in the sarcolemma. The impulse is then spread over the sarcolemma, down the t-tubules to the sarcoplasmic reticulum. As calcium is released it binds to troponin creating myosin binding sites. ATP is then split to ADP and P as the myosin head attaches to the actin filament forming a cross bridge. The release of ADP and P creates the pulling action and when ATP again binds to myosin the cycle is repeated.

Whole Muscle Contraction

Whole muscle contraction is dependent on motor units. It includes the components of nerve fiber with all the muscle fibers it is effecting. Because of this there is a all-or-none law. From the impulse they either contract or they do not. Infrequent impulses cause muscle twitches. Sumation is increased muscle contraction and tetnus is the maximal sustained motor unit contraction. Intensifying nervous stimulation activates more muscle units. In order to sustain contraction some motor units contract maximally while others are relaxed.

Muscles have four energy sources. They are triglycerides, fatty acids, glucose, and glycogen. Glycogen and triglycerides are stored i the blood. Muscles require ATP for contraction. There are three ways that muscles to get ATP. One way is by formationof ATP by the creatine phosphate pathway. The second is by fermentation and the third is by cellular respiration. The creatine phosphate pathway is the easiest and quickest way but is limited in it's storage and available for short term high intensity activities. Fermentationis also fast acting but creates lactate buldup. It creates two ATP from the breakdown of glucose. For lower intesity activities cellular respiration doesn't immediately supply ATP. It is slower because it must be carried through the blood. This process also burns fatty acids and glucose.

Muscular Disorder

Muscular disorders can be mild or serious. Common conditions include include spasms, cramps, convulsions, and sprains and strains. Inflammation in the joint is known as tendinitis. Conditions that require medical attention are fibromyalgia, muscular dystrophy, myasthenia gravis, and amyotrophic lateral sclerosis.

Homeostasis

The muscular skeletal system plays an important part in the homeostasis. It's many functions enable the body to move, regenerate, store nutrients, protect the body, maintain body temperature, and aid in the movement of fluid.

References:

http://www.mnsu.edu/emuseum/biology/humananatomy/skeletal/skeletalsystem.html

http://en.wikipedia.org/wiki/Muscle

Movable Limb Lab

2008-11-14T15:43:00.000-08:00

materials used for lab

The working model I chose for this lab is the upper forearm limb. The forearm limb shown includes the humerus, radius, ulna, and bicep muscle. The bicep muscle works with the humerus bone and radius bone. When the muscle contracts it pulls on the radius and makes the elbow flex. The following photos will illustrate the steps involved in muscle contraction.

I used a 4x4 to represent the humerus and two 2x2's to represent the radius and ulna. The red scarf represents the bicep muscle. Wire was used for the dendrites, axons, sarcomere and actin filaments. The pink string are myosin filaments and head. The brown milk duds are neurotransmitters, the white tic tac's are sodium, and the brown speckled snow caps are potassium.

The sacromere is made much larger to show the myosin and actin filaments.

2008-11-14T15:39:00.000-08:00

This is the overview

2008-11-14T15:34:00.000-08:00

Neuron with schwann cells

Movement of charged sodium and potassium ions across membrane

Propagation of action potential along axon

2008-11-14T15:25:00.000-08:00

Sarcolemma and T-tubule membrane tubes going into muscle to carry action potential throughout cell

2008-11-14T15:08:00.000-08:00

Sacromere or single actin-myosin unit

2008-11-14T14:57:00.000-08:00

Release of calcium from sacrcoplasmic reticulm.

2008-11-14T13:59:00.000-08:00

Conclusion

The model shows the action potential of a motor neuron conducting an impulse through the axon arriving at the axon terminal, causing the release of neurotransmitters (acetycholine) to cross the synaptic cleft and diffuse through the muscle membrane. The action potential is then carried through the T-tubule membrane and through the sarcoplasmic reticulum releasing calcium that creates muscle contraction within the sarcomere. This is where the actual contraction takes place. The released calcium combines with the troponin opening a site for the myosin to bind with actin. The strand of actin is pulled toward the center like a rubber band contracting. This is done by a walking action from the head of the myosin strand forming cross bridges.

The result of putting together the parts surely helped to answer so questions and filled in parts of the puzzle. Part of the challenge was finding a scale where everything might fit together. I enjoyed the project and have a better understanding of how these processes come together.

Ethical Essay

2008-11-13T22:23:00.000-08:00

Exercise for the Fun of It

Exercise is important to physical and mental health. Moderate exercise enables the body to function better on many levels. It improves functions like, increased blood supply to the muscles, decreased body fat and cholesterol, increased bone density, and many other health benefits. The long term benefits are reduced health risks later on in life.

I do feel the the environment plays a big part in the community activities that take place. I think our culture is moving toward a more sedentary lifestyle whether at work or at play. I'm hoping not to point the finger, but I think one of the factors is our use of the computer. With computer games and entertainment we can satisfy our senses without more than a click of the finger. Oftentimes parents are very busy and to keep their kids occupied they play videos for them. I sometimes see this as a daily routine and as the child gets older they are fixed on the television as their source of entertainment.

I believe that physical activity is an integral part of life. Our bodies require it to stay healthy. The renewed intake of oxygen is important to so many basic functions.

There is a difference that environment plays in either promoting or curbing physical activity. I think that community structures and accessibility play a role in inviting outdoor activity. I also think that daily activities learned in school influence habits later on in life. Physical activity is natural for children and if they learn early to have fun, they will find their own means to engage in meaningful activity later on and hopefully throughout life.

Nevertheless, it helps to live in an environment that promotes a healthy lifestyle such as parks, biking trails, and gyms and programs that are readily available to the community. In areas where there are parks people tend to gather to socialize and take leisurely walks. This type of environment encourages people of all ages to step outside and to enjoy the outdoors. When I lived near a park there were regulars who would show up to do their walk or exercise. The community seemed livelier. It was great to see a group in their seventies and eighties doing their morning stretch and exercise and daily walk. Just being around them gave me an optimistic feeling. I was hoping I'd have the same health at their age.

The guidelines presented by the Scottish government provide a helpful and hopeful means of promoting healthy lifestyles. If diabetes , heart disease, and obesity are on the rise, then perhaps our lifestyle changes in food, activity do play a part in the prevention of these diseases. I would think that the sedentary lifestyle that leads to greater risk of heart and other diseases would not be a healthy scenario to follow. In part the benefits of exercise is to reduce stress. It improves our mental and physical functioning. So exercise has the potential to reduce stress in our lives and improve our immune system.

The essay on obesity and the environment stressed that if there is sufficient pressure to adopt new behaviors individuals are apt to change for the sense of belonging. The article used recycling as a example that created a trend in educating children about it's importance. I think by setting healthy examples at a young age it helps to instill habits and behaviors that will be beneficial for a lifetime. The difficulty will be in implementing a course that will create significant change due to our current perceptions. I also agree with the article that our current culture can make it difficult to promote these changes. We are very convenience oriented. Thus there has to be a incentive for change. Unfortunately illness has become the primary motivator. Such that it has become a national epidemic. Another challenge is many people also lack the time in their lives to add additional activities to their already busy lives. So I feel that changes in the environment might lend more enthusiasm for physical activity and changes in eating habits. If it is implemented on a community level it invites others to participate. It appears that lifestyles have changed greatly in the past fifty years or so it might take incremental steps to see what results will transpire.

The Fun In Seven program started in Hong Kong sounds like a great program because it's emphasis is to provide knowledge and skills and awareness of health issues in a fun way that can be applied in life.

I wonder if adopting similar programs in the US will have such an impact.

References:

http://www.ehponline.org/docs/2005/7812/7812.html

http://octopus.bch.cuhk.edu.hk/fun7/english/about_us.shtml

Topic II Lab

2008-11-13T16:17:00.000-08:00

Movement Lab

Introduction

The purpose of this lab experiment is to determine if cold and fatigue can adversely affect muscle strength. First by observing how muscle works. Then determining what effects take place.

Hypothesis

Cold and fatigue will reduce the number of repetitions that can be completed.

Procedure

The first test will test muscle action and how it effects the size of the muscle. We will measure the circumference of the bicep at rest and the bicep when it is clenched.

In the next experiment we will perform the task of making as many clenched fists as possible in twenty seconds. This is done twice. Once in regular temperature and the other after the hand is submerged in ice for at least a minute.

In our final experiment fatigue to the muscle will be induced by repetitive action of the biceps, the large muscle of the upper arm. We will do this by squeezing a rubber ball. The idea is to get as many squeezes as possible within twenty seconds. By recording ten sets we'll have a comparison of numbers.

Conclusion

A contracted bicep is larger in circumference to a relaxed bicep.

In the second experiment the task was accomplished with 62 repetitions. However, after placing the hand in ice water the same activity of squeezing a ball produced only half of the the amount of repetitions, 31. The cold dramatically affected the functioning of the muscles.

The third experiment produced an unusual result. The amount of repetitions actually increased within the ten sets performed. The assumption is that the muscles are warming up and are able to do more. By the third round of ten sets is where change started to occur or muscle fatigue started to set in. The numbers below reflect the the round of ten sets.

What are the three changes you observed in a muscle while it is working (contracted)?

As the muscle is working contracted it gets tighter and tighter and the muscles shorten.

Also it seems that it effects the range of motion in the fingers and it relaxes less.

The muscles in the fingers and palm get thicker.

What effect did the cold temperature have on the action of your hand muscles?

Wow. The cold temperature greatly affected the number of repetition that could be completed. Due to the numbing of the hand the muscles were slow to respond and coordination was more difficult. It was near to impossible to get the muscles to relax. In repeating the repetition of squeezing the ball, the muscles did not contract and relax fully. It seems like the constriction from the cold limited blood circulation to the muscles. muscles work more effectively when there is sufficient heat and circulation.

What effect did fatigue have on the action of the hand muscles?

The effect of fatigue reduced the number of repetition that could be completed. As the movements became more difficult to complete it became harder to contract the muscles and easier the to relax the muscles although the muscles felt contracted.

Circumference of Bicep

At Rest 11 inches

Clenched 12 inches

Temperature Number of Fists

Normal 62

Ice Water 31

Trial # of squeezes in 20 sec. 9 more x's

1 55 64

2 55 64

3 56 65

4 54 63

5 52 61

6 52 61

7 52 61

8 50 59

9 47 56

10 47 56

http://www.troy.k12.ny.us/thsbiology/labs_online/home_labs/muscle_lab_home.html

2008-11-13T14:35:00.000-08:00

Sensory Receptors in Skin

Human Biology, Sylvia Mader

Saltatory Conduction

Human Biology, Sylvia Mader

Reflex Arc

Human Biology, Sylvia Mader

Compendium Topic One

2008-11-13T14:13:00.000-08:00

Nervous System & Sensory Receptors

I. Nervous System

Central Nervous System

Limbic System and Higher Mental Functions

Peripheral Nervous System

Drug Abuse

II. Sense and Sensation

Sensory Receptors and Sensations

Proprioceptors and Cutaneous Receptors

Senses of Taste and Smell

Sense of Vision

Sense of Hearing

Sense of Equilibrium

I. THE NERVOUS SYSTEM

The nervous system recieves sensory input by stimuli, processes it through the brain and spinal cord, producing an output of muscle movement or glandular secretion. There are two systems, the central nervous system (CNS) and the peripheral nervous system (PNS). The brain and spinal cord make up the central nervous system and the nerves outside the central nervous system make up the peripheral nervous system.

Nervous tissue consists of two types of cells. Neurons carry "messages" through an electrochemical process known as action potential. And neuroglia support and nourish the neurons. Neurons come in different shapes and sizes. There are three types of neurons, that perform different functions. Sensory neurons receive external stimuli by the sensory receptors which relay impulses going to the CNS. Within the CNS an interneuron integrates all nerve impulses. The third type motor neurons carry impulses from the CNS to an effector, muscle or gland that actualizes the response.

Neurons have a cell body consisting of a nucleus containing genes, cytoplasm, mitochondria and other organelles. A neuron differs from other cells because they have extensions called dendrites and axons. Dendrites bring information from sensory receptors and the axoms conducts nerve impulses away from the cell body.

The myelin sheath is a covering protecting the axom made of Schwann cells a kind of neuroglia.The spaces in sheathing is called nodes of Ranvier. The sheathing is found along long axoms and not on short axoms. The myelin serves as an protector and insulator since it has poor conductivity. Nerve areas that are not covered appear gray and areas that are covered with the sheathing appear white.

Loss of the myelin sheathing can result in the disease of multiple sclerosis an immune system impairment and luekodystrophies caused by a genetic defect.

Nerve impulses carry information within the nervous system by way of an electrochemical process. This is how neurons communicate with each other. The impulse can be measured by a voltmeter and the reading is called potential. There is a resting potential and a action potential. As it's name suggests, resting potential is when there is no impulse and the inside is more negative than the outside. The concentration of sodium ions is greater on the outside of the axon, and the concentration of potassium is greater on the inside. This unequal distribution of ions is maintained by the sodium-potassium pump. The pump works to transport sodium out and potassium into the axon. The polarity is also helped by negatively charged organic ions in the axoplasm. The rapid transmission of info is known as action potential. As this occurs there is a quick change in polarity. During an action potential depolarization is followed by repolarization. There are two types of gated channel proteins that allow an action potential to occur. First the sodium gates open to allow sodium to enter the axon. it depolarizes since the charge on the inside changes from negative to positive. Next the potassium gates open allowing Potassium to leave the axon. As the inside resumes it's negative charge it repolarizes. Nerve impulse can jump from one node to another it is known as saltatory conduction. This happens very quickly and with thick myelinated axons the rate is more than 100m/sec. Because an action potential generates another it is self propagating.

The amount of impulses generated within a fixed time determines it's intensity. A refractory period assures that the impulse passes along its intended path and does not move backwards.

The ends of the axon branch into endings called axon terminals. It is in close distance to a dendrite or cell body. The distance between the two is called a synapse and the gap is called a synaptic cleft. The signal cannot make it across, so neurotransmitters are needed to carry the message across. These molecules diffuse across through the receiving membrane and bind with receptor proteins. Different neurotransmitters produce different responses. The life of neurotransmitters at a synapse is short. This lets cells respond to new signals.

Some neurotransmitters are acetycholine, norepinephrine, dopamine, serotonin, glutamate, and GABA.

Other molecules called neuromodulators block the release of neurotransmitters or modify it's response. Substance P and endorphins are neuromodulators. They are natural painkillers.

The result of incoming signals to produce potential change are summed up in the process called synaptic integration. If the excitatory impulses surpass the inhibitory impulses threshold, action potential can occur. And if the inhibitory outweigh the excitatory the synaptic integration might prohibit the axon from firing.

Central Nervous System

Enclosed in the skull and vertabrae are the brain and spinal cord, the main components of the CNS where information is received. This is also where motor control is initiated. specific functions are performed in different parts of the brain. The spinal cord woks like a communication channel, sending and receiving info from the brain to the body. The brain and spinal cord is protected by a membrane called meninges with spacings of cerebrospinal fluid. Cerebrofluid is found in the center of the spinal cord and in the four ventricles of the brain. Fluid normally drains into the cardiovascular system. If accumulation occurs it can cause pressure.

Two types of nervous tissue are found in the CNS. Cell bodies that are nonmyelinated are known as gray matter and myelinated axons are known and white matter.

The spinal cord is a bundle of nerves that starts at the base of the brain and extends into the vertebral canal. It serves as the main pathway for information from the brain to the PNS. It is protected by the vertebral column. The nerves extend from the spinal cord and out beyond the vertebrae. The spinal cord has gray matter, white matter and a central canal. The central canal and the meninges contain cerebrospinal fluid. Sensory and motor neurons are also found here, and interneurons which communicate with the other two. There are sensory fibers in the dorsal root of the spinal nerve and the ventral root contains motor fibers. The two are joined as a mixed nerve as it leaves the vertebral canal. Spinal nerves are part of the peripheral nervous system.

Within the white matter of the spinal cord information travels to and from the brain. The left side of the brain controls the right side of the body and vise versa.

Different parts of the brain perform specific functions. The largest area known as the cerebrum integrates info which then produces motor responses. The cerebrum is divided by the corpus callosum into halves called the right and left cerebral hemispheres. Grooves known as sulci make distinct the lobe areas such as the frontal, parietal, occipital and temporal. Thus there are four lobes per hemisphere. These are the areas where movement, reasoning, somatic, sensing, hearing, and vision take place. The cerebral cortex is the outer layer of the cerebrum. Wernicke's area and Broca's area are two centers important to our ability to speak and are located in the left cerebral cortex. The diencephalon area in the third ventricle contains the hypothalamus and thalamus. The hypothalamus is important to several functions such as homeostasis and controls the pituitary gland. The thalmus is important to functions such as memory and emotions thus it receives visual, auditory, and somasensory information. The cerebellum is important to posture and balance. It integrates and sends impulses to the muscles. The brain stem contains axon bundles known as pon which link the cerebellum to the central nervous system. Within the brain stem the midbrain works as a relay, the medulla oblongata above the spinal cord is a reflex center performing many functions such as the regulation of heartbeat, breathing, and blood pressure. Along the brain stem is a mass of fibers and nuclei called reticular formation which receives and sends sensory signals.

Limbic System and Higher Mental Functions

This system is involved in the process and functioning of emotions, memory, and learning resulting in our behaviors. There are two main structures. Through the amygdala we experience emotions. And the hippocampus is an area important to learning and memory. Learning and speech require memory thus the three functions are interrelated.

Peripheral Nervous System

This system consists of cranial nerves and spinal nerves and carries impulses to and from the central nervous system. Cranial nerves project from the brain and spinal nerves from the spinal cord. Nerves are made up of axons. Cranial nerves come in twelve pairs consisting of sensory, motor, or mixed fibers and are attached to the brain. Spinal nerves come in thirty one pairs containing both sensory and motor fibers.

The peripheral nervous system is comprised of the somatic and autonomic system. The somatic carries impulses to the central nervous system and away form the central nervous system to the skeletal muscles, skin and tendons. Involuntary actions that are produced are called reflexes. A reflex arc describes the path of the spinal reflex. The autonomic system is connected to the activity of the cardiac and smooth muscle glands. Within this system there are two complimentary involuntary pathways called the sympathetic and parasympathetic. The sympathetic produces responses associated with an alert state and the parasympathetic produces responses associated with a relaxed state. Norepinepherine and adrenaline are produced in a sympathetic response and acetycholine is producced in a parasympathetic response.

Drug Abuse

Neurological drugs block or activate the action of neurotransmitteres at a synapse, and can alter the nervous system. Drug abuse can lead to psychological or physical dependency on the drug. once it becomes a dependency it can lead to addiction. The most common forms of drug abuse is alcohol, nicotine, cocaine, methamphetamine, heroine, and marijuana.

II. SENSE

The human body consists of a variety of sensory receptors that are able to detect different stimuli. These impulses are carried to the central nervous system.

Sensory Receptors and Sensations

Sensory receptors carry impulses to the spinal cord and brain. There are four kinds of sensory receptors. They are called chemoreceptors, photoreceptors, mechanoreceptors, and thermoreceptors. Chemoreceptors respond to chemical substances as pain receptors are a type of chemoreceptor. Photoreceptors respond to light, mechanoreceptors respond to forces such as pressure, and thermoreceptors such as in the skin are sensitive to temperature. When impulses reach the cerebral cortex it registers a sensation. Our interpretation of the sensation creates our perception.

Proprioceptors and Cutaneous Receptors

Proprioceptors are helpful to equilibrium and posture. They are mechanoreceptors important to reflex and muscle tone. Muscle tone is controlled by the action of the muscle spindle which increases contraction and the golgi tendon organ which deceases contraction. Cutaneous receptors are another type found in the dermis layer of the skin. They enable us to feel touch, pressure, pain, and temperature. The skin also contain pain receptors known as nociceptors that are sensitive to chemicals from the release of damaged tissues.

Senses of Taste and Smell

The act of tasting and smelling is made possible by chemoreceptors. They are able to respond to direct and distant stimuli. The receptors are able to bind to molecules. Different areas of the tongue sense various tastes and flavors. our sense of smell is produced by the olfactory cells in the nasal cavity. olfactory cells are neuronsthat transmit this info to the cerebral cortex.

Sense of Vision

The eye, optic nerves and areas of the cerebral cortex are all involved in the visual process. The eyeball has three layers. The sclera, choroid, and retina. The retina is where the sensory receptors cones and rods are located. The lens and the cornea work to focus light on the retina. The image is then carried by the optic nerves to the thalmus and on to the occipital lobe of the brain. Common disorders of the eye are nearsightedness, farsightedness, and astigmatism. These conditions involve the changing shape of the eyeball. Color blindness is normally hereditary and affects the cones ability to perceive light and colors. Other problems that can develop with age are cataracts, clouding of the lens, and glaucoma, fluid pressure in the eyes.

Sense of Hearing

Sensory receptors for the hearing are mechanoreceptors located in the inner ear. The are important to hearing and balance and involve the ear, cochlear nerve, and the cerebral cortex. There are three parts to the ear, The outer, middle, and inner. The structure serves to amplify and direct sound waves to the inner ear. It is within the inner ear where we find the mechanoreceptors which are hair cells. Nerve impulses travel from the receptor to the cochlear nerve on to the cerebral cortex.

Sense of Equilibrium

The ear is also the responsible for maintaining equilibrium. Within the inner ear mechanoreceptors in the semicircular canals help to sense the heads rotational equilibrium and gravitational equiliibrium. also within the inner ear the utricle is sensitive to horizontal and vertical movements.

References:

http://www.sciencedaily.com/articles/s/sensory_neuron.htm

http://en.wikipedia.org/wiki/Spinal_cord

http://faculty.washington.edu/chudler/cells.html

2008-11-13T08:35:00.000-08:00

Nervous Function Lab

2008-11-11T20:05:00.000-08:00

2008-11-11T20:04:00.000-08:00

Nervous Function Lab

1. What is the electrode measuring?

The electrode is measuring the activity within the neuron. The resting/action potential of the neuron.

2. Why use leeches in neurophysiology experiments?

Leeches are used in these experiments because the neurons in their nerve cord are large and easy to get to.

3. What is the difference between a sensory and motor neuron?

A sensory neuron transmits nerve impulses to the central nervous system and a motor neuron carries nerve impulses away from the central nervous system to the muscles or glands.

4. How do you think a leech experiences pain? What is pain?

Pain is experienced by the signals sent by a specific kind of sensory neurons called pain receptors. I would think that leeches feel pain because they have a nervous system and sensory receptors.

5. What are the two most interesting things about doing this lab?

I found that actually seeing how the electrode measurement worked gave me a better idea of what is involved in measuring potential. The next was clicking through the different cell types to see what they looked like under the microscope.

6. Anything you found confusing or did not like about the lab?

I didn't find it confusing. I was actually glad that this lab was done in a virtual setting.

Self Evaluation

2008-10-27T13:59:00.000-07:00

What were the three aspects of the assignments I've submitted that I am most proud of?

I'd have to say completion and format.

What two aspects of my submitted assignments do I believe could have used some improvement?

Organization and timeliness.

What do I believe my overall grade should be for this unit?

Somewhere in the B's

How could I perform better in the next unit?

Preparation and improving skills to load on blog.

At what moment during this unit did you feel most engaged with the course?

As the course continues, I'm but enjoying how the materials presented is piecing together. I spent a lot of time on the section about the heart.

At what moment did you feel most distanced from the course?

Loading the assignments to the blog site. It can be a little challenging.

What action that anyone (teacher or student) took during this unit that you find most affirming and helpful?

Thank you for the extension.

What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?

I did not experience this

What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.)

The links to the ethical essays section were sites that really interest me, and I'd want to look into them more.

Cardiovascular System and Blood

2008-10-27T04:38:00.000-07:00

Cardiovascular System And Blood

I. Cardiovascular System

The Heart

Blood Vessels

Cardiovascular Pathways

Disorders

II. Blood

Function and Composition

Red Blood Cells

White Blood Cells

Platelets

Sickle Cell

Blood Types

Blood Pressure and Pulse

The Cardiovascular System and Blood

The cardiovascular system distributes blood throughout the entire body. The heart works as a pump distributing blood through a network of blood vessels with which the blood flows. The blood carries the substances to be exchanged at the cellular level and is important to cell functioning.The circulation of the blood refreshes the cells in all parts of the body in several ways. When blood enters the lungs, oxygen enters and CO2 leaves. As the blood enters the kidneys the wastes are filtered, and nutrients are picked up in the intestines. Amino acids are absorbed in the blood and proteins and fats are returned. The lymphatic system collects excess tissue fluid and sends it to the cardiovascular system. Both blood and lymph are tissue fluid

The Heart

The heart is a muscular organ that sits behind the sternum in the chest area. It is acorn shaped with the apex tilted slightly to the left. There are four chambers, divided to the right and left by the sternum. The are two upper chambers. The right atrium receives oxygen depleted blood from throughout the by the inferior and superior vena cava. And the opposite is true for the left atrium which receives oxygen rich blood from the lung by the pulmonary veins. Blood is pumped from the lower chambers called ventricles. Because of this they are thicker and more muscular. The right ventricle sends oxygen depleted blood to the lungs by the pulmonary arteries. And the left ventricle sends oxygen rich blood throughout the body through the aorta. It is known as a double pump because the left ventricle sends blood throughout the body and the right ventricle sends blood to the lungs. Myocardium is the cardiac muscle lining the heart walls.

To keep the flow of blood in the right direction and to prevent backflow the heart has four valves. Two atrioventricular (AV) valves are between the atria and ventricle. The valve on the right is called the tricuspid valve and the valve on the left is the bicuspid. They are both held up by stringlike supports that attach to the walls of the heart. The other two valves called semilunar valves prevent backflow as blood is leaving the heart. The pulmonary semilunar valve on the right and the aortic semilunar valve on the left.

Heart contraction moves blood throughout the body with it's pumping action. This contraction is known as the heartbeat. There are two beats that make up the cardiac cycle. The first contraction of both atria and the second contraction of both ventricles making the sound "lupdup". The contraction or working phase is called systolic and at relaxation it is called diastolic. Intercalated disks lets cells of the atria and ventricle contract by conduction. Pericardium is the thick covering around the heart having two layers with the inner layer secreting a fluid that allows the heart to move when it beats.

An internal conduction system of nodal tissue is located in two areas of the atrium. This cardiac muscle tissue has nervous and muscular functions. The heartbeat is initiated in the upper right atrium by the sinoatrial node contracting the atria then as the signal reaches the atrioventicular node at the base of the right atrium the ventricles contract.

Working together with other parts of the body, the medulla oblongata controls parasympathetic and sympathetic responses of the heartbeat. Hormones from the Adrenal medulla can stimulate the heart to beat faster.

Blood Vessels

There are three types of blood vessels, arteries, capillaries, and veins. Each serve a different purpose. Arteries distribute blood throughout the body, capillaries facilitate exchange of substances and veins collect blood from the body.

Arteries carry oxygen rich blood going away from the heart. Made up of three layers, the endothelium is the thin inner layer. Muscle tissue and a thin layer of elastic form the middle layer and connective tissue form the outer layer. Arteries are thicker and under more pressure. Arterioles are smaller arteries that branch into capillaries. When they constrict or dilate it effects blood pressure. By placing the middle and index fingers against the blood vessels of the radial or carotid artery a pulse reading can be taken that equals the heart rate. Other areas where the pulse can be felt are in the arteries close to the skin. Other than the carotid and the radial there are five others: the brachial on the upper arm, aortic arch by the heart, abdominal aorta by the stomach, femoral arteries on the thigh , and the popliteal arteries near the knees. The average heart rate is between 60 to 80 beats per minute for adults.

Capillaries are microscopic vessels found throughout the body covering about 6,300 sq. meters. Made up of a single thin layer of endethelial cells the thin layer allows diffusion of oxygen, carbon dioxide, nutrients and wastes. Blood capillaries re-circulate blood and lymph capillaries help rid waste. Where exchange takes place is in the capillary bed, a web of vessels between an arteriole and a venule. Exchange is caused by blood pressure and osmotic pressure. Water leaves the capillary ends by difference in pressure at the arterial end and in reverse water moves into capillary ends by difference in pressure at the venule end. Wastes and carbon dioxide are diffused into capillaries. However, red blood cells and plasma proteins are too large to exit capillaries. Capillaries are also found surrounding the alveoli in the lungs. The thin tissue of alveoli lets oxygen cross through to red blood cells where hemoglobin holds oxygen.

Veins collect blood to return to the heart and are similar in structure to arteries. Also made of the same three layer as arteries but having a thinner middle and outer layer. This makes them thinner. Veins have one-way valves that prevent backflow. There is less pressure in veins and so the flow of blood is assisted by three factors. Veins have one-way valves to regulate flow going to the heart. The skeletal muscle pump contracts the muscles causing blood to move and the respiratory pump expands the thoracic cavity in an action that moves blood as well. Between a vein and a capillary there is a venule.

Cardiovascular Pathways

There are two pathways for the circulation of blood. Blood reaches the lungs by the path of the pulmonary circuit. The circuit loops from the body to the right atrium, pulmonary trunk, right and left pulmonary arteries and then to the lungs. From the arterioles blood is delivered to the capillaries where carbon dioxide is released and oxygen is absorbed. Then the pulmonary venules lead to the four veins and to the left atrium. Pulmonary arteries carry oxygen poor blood and pulmonary veins carry oxygen rich blood. Blood reaches body tissues by the systemic circuit. The left ventricle sends the blood to the aorta then throughout the body. It returns to the heart from the inferior and superior vena cava into the right atrium. The superior vena cava returns blood from the head, chest , and arms. And the inferior vena cava returns blood from the lower parts of the body. Coronary arteries supply blood to the heart and branch off the aorta. The hepatic portal system transports blood from the digestive tract to the liver.The hepatic portal vein carries oxygen depleted blood containing glucose and amino acids. The liver stores glucose and purifies the blood. Blood then leaves the liver by the hepatic vein.

Cardiovascular Disorders

The leading cause of death in the western world and on the rise in other countries. Cardiovascular diseases can cause heart attack, stroke or kidney failure. Hypertension is a condition of abnormally high blood pressure. It can be caused by stress diet and a number of other reasons. Damage can occur to the vascular system or heart and prolonged hypertension can create other complications and lead to stroke or heart attack. Normal blood pressure is considered to be 120/80 but in recent years it has been increased to 130/80. Atherosclerosis is caused by plaque lining the walls of the arteries and high cholesterol levels. The risks are blockages in the arteries that can lead to heart attack or stroke. Pain radiating in the left arm is a symptom of possible heart problems.

BLOOD

A liquid medium for transport, defense and regulating. It is composed of tissue cells

Function and Composition

Blood carries oxygen and nutrients to the tissues and carries away waste. It transports hormones to tissues for cell metabolism and contains blood cells that defend against pathogens. Some secrete antibodies that help to destroy pathogens and unwanted microbes. Blood also helps to regulate temperature and water-salt balance. Blood is a tissue fluid made up of cells, consisting of water and proteins. The liquid part is called plasma. Plasma proteins made by the liver help to maintain pH. Major plasma proteins include albumins which carry organic molecules to form osmotic pressure, fibrinogens form blood clots and three types of globulins. Alpha and beta transport hormones, cholesterol and iron, and gamma is made in white blood cells.

Red Blood Cells

Red blood cells (RBC) do not have a nucleus and lack most organelles. Through mitosis they replicate DNA rapidly and it's production is effected by oxygen. They contain plenty of hemoglobin which gives the cells it's red color pigment. They are produced in the bone marrow. The unique concave shape allows for more surface area for diffusion to occur and is used to hold oxygen. How much oxygen? Each cell can carry over a billion copies of oxygen. The cells destroy very rapidly and replicate very quickly in the liver and spleen. Anemia occurs if someone has an insufficient number of red blood cells or not enough hemoglobin. Sickle cell disease is is a blood disorder caused by the irregular shape of the cell which ruptures as it passes through the capillaries thus increasing red cell destruction. It is a chronic and lifelong disease that can shorten life span. And is an inherited condition.

White blood cells

Serving the function of immunity white blood cells ( leukocytes) fight pathogens and are larger than red blood cells. Produced in the bone marrow they can double within hours. They exist in tissue fluid and lymph because they are able to squeeze out of capillary walls. Some white blood cells are able to surround and destroy pathogens in a process called phagocytosis. Others secrete antibodies and mark unwanted invaders for removal. A protein called colony stimulating factor regulates the various types of white blood cells. There are two types of white blood cells. Granular leucocytes and Agranular leucocytes which do not have granules. Granular leucocytes consist of neutrophils, the most abundant, they are phagocytic and act as first response bacterial invasion. Basophils release a substance to trigger other cells and eosinophils multiply in response to allergy or infection. There are two types of agranular leucocytes, lymphocytes and monocytes. The second most abundant white cells lymphocytes consist of T cells and B cells. B cells make antibodies and T cells destroy pathogens. Monocytes are the largest and can become macrophages. They become dendritic cells in the skin and phagotize old cells, debris and pathogens.

Platelets

The process of blood clotting is assisted by platelets (thrombocytes). When a vessel is punctured or damaged clotting takes place to stop the bleeding. The platelets coagulate to form a clot. Platelets are also produced in the red bone marrow. Thrombocytopenia happens when platelet count is low resulting in nosebleeds, bruising, bleeding in the mouth, intestines and brain. Hemophilia is an inherited clotting disorder. Someone who has this condition bleeds easily.

Sickle Cell

This is a hereditary blood disorder that causes abnormal production of hemoglobin. The red blood cells become deformed, (shape of a sickle) as a result it cannot carry enough oxygen and easily break apart or create a condition of low or insufficient hemoglobin. Some will stick together causing blockages. The result of reduced oxygen will lead to tiredness, poor tissue development and malfunction of major organs leading to death. The cell mutation is a error in the DNA code that lets the body know how it should form hemoglobin. When sickle cell disease was recognized, clinicians saw that it ran more in families of African descent.The sickle cell gene is prevalent in Africa in areas with malaria. Researcher found that this trait benefited those in areas with malaria. It requires the individual to inherit both genes in order to acquire this disease.

Blood Types

Determining blood type is important in transfusions. Two distinctions the ABO group and Rh group make up blood type. There are four combinations to the ABO group. Type A, B, AB, and O. Type A carries the A antigens and anti-B antibodies, type B the B antigens and anti- A antibodies, type AB the A and B antigens, and type-O the anti- A &B antigens. The second distinction Rh blood group determines the Rh factor of antibodies.

Blood Pressure

Blood pressure moves blood in the arteries and is measured by a sphygmomanometer at the brachial artery. The greatest pressure is called systolic and the lowest pressure when the heart is at relaxation is called diastolic. Normal blood pressure is 120/80. Hypertension is the result of high blood pressure and hypotension is the result of low blood pressure.

References:

en.wikipedia.org/wiki/Heart

http://www.howstuffworks.com/heart.htm

http: // tutorials.com/09/0902/0902.asp

Lymphatic System and Immunity

2008-10-27T04:06:00.000-07:00

http://quest.arc.nasa.gov/projects/flies/humanImmune.html

Lymphatic System Immunity and Microbes

I Microbes and Pathogens

II. Lymphatic System

III. Nonspecific Defenses

IV. Specific Defenses

V. Acquired Immunity

VI. Hypersensitivity Reactions

V. AIDS

Lymphatic System Immunity and Microbes

The Lymphatic system works in conjunction with the cardiovascular system in aiding immunity.

Microbes and Pathogens

Bacteria or microbes are everywhere and beneficial to life. However some are harmful to humans and are known as pathogens mainly bacteria and viruses. Bacteria are prokaryotes, don't have a nucleus and are independent cells. They reproduce identical copies by binary fusion. Disease is caused by the growth of bacteria or the release of toxins. Common diseases are strep throat, tuberculosis, syphilis, and food poisoning.

Viruses are chemicals that require a host so they are said to be acellular and cannot live independently. They consist of two parts, an inner core of nucleic acid and the outer caspid of protein units. It relies on the enzymes and ribosomes of the host for reproduction and unlike cellular organisms it doesn't need DNA, but may use various enzymes or an RNA genome. Colds, flu, measles, chicken pox, polio, and AIDS are viral.

Lymphatic System

This system consists of the lymphatic vessels and organs functioning to maintain homeostasis. To do this there are four main functions. Excess tissue fluid is absorbed by the lymphatic capillaries emptying into the bloodstream. Fat is carried to the blood by capillaries in the small intestines called lacteals. Lymphocytes are produced and the system protects against pathogens.

The Lymphatic vessels consist of capillaries, vessels and ducts that empty lymph into the cardiovascular veins in the shoulder. Lymph is colorless and contains lipids. There are two ducts, the thoracic duct and the right lymphatic duct.

The primary lymphatic organs are bone marrow and the thymus gland, and the secondary are the lymph nodes and spleen. White blood cells mature in the bone marrow with the exception of T cells which pass through the thymus. The secondary organs purify and monitor the lymph. The spleen is the largest lymphatic organ where macrophages engulf debris and pathogens. Lymph nodes filters lymph in compartments where macrophages also engulf debris and pathogens.

Nonspecific Defenses

All pathogens are met by barriers to entry and the inflammatory response. The body's first line of defense the skin and mucous membranes serves as a barrier to infection. Chemical barriers also defend the body. Secretions from oil glands of the skin have chemicals that weaken or kill bacteria. Lysozyme in saliva, perspiration, and tears is antibacterial. Urine flushes bacteria from the body and stomach acids kill or prevent the growth of bacteria. Lastly, natural flora in the mouth, intestines, and elsewhere create a protective barrier to combat pathogens. Antibiotics reduce the effectiveness of normal flora. The second line of defense the inflammatory response sends neutrophils and macrophages to engulf pathogens. A group of complement protein assist in the immunity.Blood plasma proteins called complement proteins trigger histamine and attract phagocytes. A membrane attack complex creates holes in bacteria and viruses causing them to burst. Interferons bind to receptors and interfere with viral replication.

Specific Defenses

If nonspecific defenses are unsuccessful in preventing infection, specific defenses are prompted to destroy the disease causing agent. Antigens are foreign invaders such as bacteria, mold, viruses, molds, and parasitic worms. Some cancer cells are antigens. Lymphocytes are the main specific defense. It is able to differentiate into other types of B cells and T cells. By recognizing antigens their receptors bind with the antigen. Antigens are numerous so there is a large diversity of B cells and T cells to protect the body. B cells and T cells are able to clone themselves if they bind with an antigen.

B cells perform anti-mediating immunity by differentiating into plasma cells and memory B cells. The receptors of the cell must fit the antigens shape for it to expand. B cells, are made in the bone marrow that become plasma cells that produce and secrete antibodies. As B cells clone they sometimes become memory cells. This enables long term immunity. Apoptosis, the programmed death of cells happens when the likelihood of infection subsides, and the the cells are no longer needed.

Shaped like a Y, antibodies are protein cells with two arms. Each arm having a long polypeptide chain and a short polypeptide chain. At the trunk, there are constant regions, where the sequence of amino acids is set. The structure of the constant region determines the class of the antibody. These proteins are made by transcription

and translation of DNA.

There are five classes of circulating antibodies. IgG are mainly found in the blood, lymph, and tissue fluid. It can cross the placenta giving a newborn partial immunity.IgM antibodies activate the complement system and appear quickly after an infection. IgA have two Y-shaped structures found in body secretions. IgD antibodies serve as receptors on B-cells. IgE prevent parasitic worm infections and can prompt allergic responses.

T cells attack diseased cells and cancer cells by the action of cell -mediating immunity. T cell receptors (TCR) bind to invaders. Cytotoxic T cells or macrophages then engulf the invading microbe.T-cells recognize antigens with the help of an antigen presenting cell (APC) such as a macrophage. APC' s travel to the spleen and lymph node, after phagocytizing a pathogen. Helper T cells secrete cytokines that assist in the response of all types of immune cells. T cells.

Acquired Immunity

There are two types, active, when the individual produces the antibody and passive, when it is given as an injection. A individual can develop an immunity to a pathogen. It is also common to induce active immunity by immunization. Vaccines have antigens of the pathogens. Active immunity is longer lasting and is dependent on the presence of B cells and T memory cells. Individual with insufficient antibodies can receive injections of antibodies or immune cells but they are short lasting since the body does not produce it's own.

Hypersensitivity Reactions

Allergies can result in tissue damage, brought about by hypersensitivity to substances. Sometimes the reaction is immediate and is caused by the antibody IgE. Anaphylactic shock happens as the allergen enters the bloodstream. Delayed reactions is initiated by memory T cells. Tissue rejection is when the immune system recognizes that a tissue is not "self" as in transplants.

AIDS

Acquired immune deficiency syndrome is a set of symptoms and conditions resulting from the virus caused by (HIV) human immunodeficiency virus. This condition weakens the immune system and leaves the individual susceptible to opportunistic infections. HIV is transmitted through contact bodily fluid to the blood or mucous membrane. HIV is a retrovirus of a single strand of DNA surrounded by proteins. It enters the cell where it replicates by the transcription of RNA. As it gets into the cell it integrates into DNA. From there it can make hundreds of copies of itself with RNA. As it duplicates it buds out. HIV infects helper T cells calls in cells to kill own cells, thus without T cells immunity is compromised.

After infection it makes many copies and the helper T cells drop within 3-6 weeks. THe antibodies stimulate a response. HIV in the blood drops to nothing in 12 weeks. The antibodies and helper T cells are ready to attack after 3 months so the illness goes into clinical latency. As the number of helper T cells star to drop there aren't enough cells to mount a response. This is when opportunistic infections take hold. HIV doesn't kill but weakens the body's defenses.

An estimated 37 million people worldwide live with this disease and it has killed an estimated 2.5 million. AIDS is a pandemic with over three quarters of the deaths occurring in sub-Saharan Africa. Some researchers believe that it originated in sub-Saharan Africa during the twentieth century. It was initially recognized by the Center for Disease Control and Prevention in 1981.

Nutrition

2008-10-27T04:03:00.000-07:00

Food and Nutrition

I. Overview of Digestion

First Part of the Digestive Tract

The Stomach and Small Intestine

The Three Accessory Organs & Regulation of Secretions

The Large Intestine

II. Nutrition

Overview of Digestion

The organs of the within the gastrointestinal tract make up the digestive system. Foods are broken down to unit molecules, sugars, amino acids, fatty acids, and glycerol, so it can be transported by the blood to the cells. Digestion requires ingestion, movement, absorption, and elimination. Ingestion takes place in the mouth by chewing the food. Digestion is mechanical when food is divided into pieces in preparation for digestive enzymes and occurs in the stomach and mouth. Chemical digestion starts at the mouth and ends at the small intestines. Movement of the GI tract passes food from organ to organ. When the unit molecules cross the walls of the tract absorption occurs. Elimination is the removal of unwanted wastes.

The Gi tract resembles a garden hose that has four layers. The first layer the mucosa protects the wall from the enzymes and produces mucus. The submucosa the second layer protect against disease and responds by inflammation. It is made of connective tissue, blood vessels, lymphatic vessels and nerves. The third layer contracts to move food along the tract. It contains two layers of smooth muscle. The fourth outermost layer the serosa secretes serous fluid.

First Part of the Digestive Tract

The mouth, pharynx, and esophagus make up the first part of the digestive tract. From the mouth food is taken in which begins the process of mechanical and chemical digestion. Salivary glands produce an enzyme, salivary amalase that starts the process of digesting starch. As chewing starts mechanical digestion occurs. The food passes the pharynx as is is swallowed. It is at this point that the food can go the wrong way like to the nasal passages. The action of peristalsis pushes the food along the esophagus where chemical digestion takes place. At the stomach a sphincter lets food pass as it is relaxed but when the contents back up along the esophagus, acid reflux known as heartburn occurs.

The Stomach and Small Intestine

Digestion is completed at the stomach and small intestine. The stomach is sack shaped sitting beneath the diaphragm. It does not absorb nutrients but mechanically breaks down food with gastric juice. The juice contains pepsin that digests protein, hydrochloric acid (HCI) and mucus. HCI breaks down connective tissue in meat. The small intestine is long and narrow in diameter. Enzymes within the intestine digest primary carbohydrates, proteins, and fats. The duct at the duodenum receives secreted enzymes from the pancreas and bile from the liver and gallbladder to emulsify fat and hydrolyzed to glycerol and fatty acids by lipase in pancreatic juice. The digestion of carbohydrates and glucose starts with amylase and is completed by intestinal enzymes. And proteins and amino acids are broken down by trypsin and an intestinal enzyme. The intestine have a slightly pH balance.

Absorption of sugars, amino acids, fatty acids, and glycerol occur in the walls of the small intestine. Fingerlike projection call villi line the walls of the intestine and extensions called microvilli provide more surface area for absorption. It is here in the villus where nutrients are absorbed, the lacteals of the villus, a small lymphatic capillary. Sugars and amino acids enter the blood capillaries of the a villus and glycerol and fatty acids the epithelial cells. From this they reach the cells by the blood.

The Three Accessory Organs & Regulation of Secretions

These three organs include the pancreas, liver, and gallbladder. A grayish pink fish shaped organ stretched behind the stomach. It produces pancreatic juice, and is also an endocrine gland that secretes insulin. Insulin is a protein usually secreted after a meal stimulating cells to take up glucose for storage or metabolism. If the blood glucose level is too high insulin is produced to to regulate glucose. Type 2 diabeties is the result of this extended condition. Type 1 diabetics produce no insulin. The liver and pancreas regulate constant blood glucose level.

The liver sits below the diaphragm consisting of approximately 100,000 lobules performing various functions. It filters blood via the hepatic portal vein from the capillary bed of the GI Tract and into the capillaries of the lobules. Besides glucose it also stores iron and vitamins A, D, E, K, and B12. Plasma proteins are made in the liver and cholesterol is also regulated here. The liver makes bile that is stored in the gall bladder, a pear shaped organ below the liver. Gallstones are created here. It's other functions are destroying old rbc's , excreting bilirubin, and producing urea after breaking down amino acids.

The nervous system and digestive juices control digestive juices. The smell of food stimulates gastric secretions. Gastrin is made after eating a protein rich meal. Other hormones made in the duodenal are secretin and CCK (cholecystokinin). Secretin is secreted by acid and fat and protein stimulate the release of CCK.

The Large Intestine

Shorter but wider than the small intestine it includes the cecum, colon, rectum, and anal canal. At the end of the cecum lies vermiform appendix for fighting infections. Appendicitis is when it becomes infected. The colon follows the right side, where the traverse colon then crosses and follows the left side as the sigmoid colon enters the rectum which opens to the anus where defecation occurs.

The Function of the large intestine is to absorb water and vitamins made by intestinal flora and to break down indigestible material, and to produce B complex and vitamin K. Feces are formed of water and solids. The solids comprise of bacteria, fiber, and indigestible materials. Defecation is assisted by peristalsis. Feces collect in the rectum, nerve impulses contract the rectal muscles and the anal sphincters relax allowing feces to exit through the anus.

Nutrition

Classes of Nutrients

Nutrients assist in providing energy, cellular metabolism and growth and development. Carbohydrates are simple or complex. Used as the body's energy source, carbohydrates are needed to convert to glucose. The brain requires glucose. Cakes, cookies and white bread are refined so they lack nutrients. The healthier choice are complex carbs such as beans, whole-grains, nuts and fruits which supply nutrients and fiber. A diet high in refined carbs can cause health issues. Refined carbs have a high glycemic index (GI) that creates a response to glucose by overproducing insulin. This may lead to insulin resistance or diabeties type 2. The amino acid in proteins are essential to the body's functions. Deficiency in one leads to complications. Amino acids are found in legumes, vegetable, nuts, but are most plentiful in meats. Limiting proteins is harmful for the body. Too much protein leads to cause dehydration or kidney stones. Lipids include fats, oils, and cholesterol. Saturated fats can cause plaque and caardiovascular disease they are mainly butters and meats. Unsaturated fats or essential fatty acids come from plant sources like corn and safflower. Olive oil contain more monosaturated fatty acids. Omega -3 in olive oil is said to protect against heart disease. Salmon trout, and sardines are another good source. Trans-fatty acids are hydrogenated and may reduce the function of cell membrane receptors that clear cholesterol from the blood. they are found in vegetable shortening and commercially packaged products.

Minerals

Minerals are comprised of major and trace minerals. They are important to cll constitution, body fluids and tissues. Stress can reduce magnesium and a high fiber diet can deplete zinc. Calcium is essential to bones, teeth, nerve conduction, and muscle contraction. When it is deficient osteoporosis can set in. Sodium is very important in regulating the body's water balance. Hypertension is the result of excessive salt intake. Thus the balance of mineral intake is important.

Vitamins

The body utilizes vitamins for metabolic functions. There are 13 vitamins which are either water soluble or fat soluble. Antioxidants counter free radicals. Vitamin C, E, and A. are antioxidants and are found in fruits and vegetables. The food pyramid suggests a portion of fruit and vegetables daily. Vitamin D found in milk protects against rickets.

Nutritious Meals

Many health problems are the result of diet. A person can determine the calories needed for daily activity and cut back calories that is not needed. By using the food pyramid as a guide you can distribute those calories in planning a more nutritious meal.

Eating Disorders

Eating disorder involve personal, cultural, emotional, and biological factors. Often a person is not happy with their self image.the conditions of anorexia, bulimia and obesity can cause health problems such as malnutrition, disability and even death.

2008-10-24T01:23:00.000-07:00

-How healthy a daily diet do you think this is? Why?

I think overall it's a fairly healthy diet. According to the 2005 USDA food guide the two food groups I did not include were fruits and milk. The meal contained protein from fish with a balance of carbs and vegetables. The chart shows that the daily requirements were fulfilled for vitamins and minerals.

-What would you change about this day's eating, if anything?

According to the chart my sodium intake is above what it needs to be. And the carb count is on the slightly high side as well. I could possible substitute steamed vegetables or soup that is low in sodium. I don't drink milk, so I guess soymilk might be be a replacement. I was glad to see that the saturated fat and cholesterol were within healthy limits

-Do you find this kind of nutritional tracking helpful? Why or why not?

Calculating percentages of nutritional value for a day or for a sitting is something I've never done. I was surprised by some of the numbers. My main concern was the sodium and carbs. I think the site is helpful and fun and easy to use. It gives me a better idea of my overall eating habits.

Food for Thought

2008-10-24T00:18:00.000-07:00

We have a wide variety of food choices today. There are conventionally grown foods, organic foods and restaurants that serve organic only, vegetarian, raw, etc. We are exposed to so many different cultural cuisines that lend variety to the foods we consume, prepare, and purchase. I think the current American diet allows for a lot of versatility.

Growing up, I remember my diet consisting largely of what was available at the local supermarkets. Most of the processed foods contained a lot of salt, hydrogenated oils, sugar, and preservatives. The foods were typical of the commercial American diet. I remember our most common foods such as spaghetti, meatloaf, Campbell soup, Hostesss cup cakes, chips and pasteries, although I didn't care much for sodas. What we knew was that the four main food groups are important for a healthy and well rounded diet. However, it did not address issues such as the quality of foods or processed and packaged foods. So we would put a handful of potato chips on the side and that would be our carbohydrate requirement. My mother was more in favor of natural foods but we tended to adopt the current trends of eating. We did have homestyle meals like chicken soup and stuffed cabbage corned beef,etc. and plenty of fruits and vegetables.

Thanksgiving was probably the busiest time when we gathered to help out in preparing the evening meal. Other than that we were often preoccupied with other things and meal times were not much of an event. I've since come to appreciate how some cultures utilize meal times as a time for relaxation and socializing. It adds another dimension to life. I think there is value in some cultures that hold significance to harvest, ceremony and preparation.

When foods are grown locally there is a community that supports and is more conscience of the environment. Local farmers tend to care more about the crops they produce for their community. They are often more in touch with the communities needs and in some areas such as the coast of California and Oregon there are numerous small farms that sell their crops when it is seasonally best. This provides the consumer with better quality foods.

What I also find is that some diets are more concerned with convenience and lack nutritional value. The diet I grew accustomed to no longer appeals to me because I now feel healthier eating other foods. Knowing this I try to choose foods that are more nutritious in nature. This would include natural foods and not fortified foods. And have recently started to read about and have tried making foods that are healthier for the body. For some time it was my thought that I would have to give up flavorful or hearty foods to eat healthy. Now I'm finding that this is not true and am very interested in trying new recipes and find that not all are difficult or time consuming. Some are very simple, have less calories, and are surprisingly flavorful and nourishing for the body and mind.

I think the issue of nutrition is different from individual to individual and from culture to culture. From my own experience I tend to rotate between certain foods and eating habits. I might stick to vegetables and grains and very little meat and mostly fish. Or depending on my energy level and how my body feels I might switch to mostly fruits and vegetables. I don't often have meat as my main course. The changing of my diet resembles the Chinese theory of eating different foods for changing seasons and adjusting to the bodies needs.

It seems that our culture is constantly reinventing specialized diet, such as the Low Carb Diet, South Beach Diet, etc. And we go through phases of what's popular such as Thai, Mediteranean, Japanese, to name a few. Because we are constantly experimenting, I feel the American diet will always be changing.

Lab Data

2008-10-23T22:02:00.001-07:00

2008-10-22T17:59:00.000-07:00

Exercise Physiology Lab Project

2008-10-22T14:43:00.000-07:00

Unit II Exercise Lab Project

Purpose:

This lab project will involve gathering the data needed to determine how different activities affect the the metabolic rate. The four measurements that will be recorded are pulse, respiration rate, systolic blood pressure, and diastolic blood pressure. Each activity is performed five times and the mean is recorded. The results will determine how activity affects the cardiovascular and respiratory system. The mean numbers are graphed and compared to determine if the data supports the following hypothesis.

Hypothesis:

With increased activity there will be an increase in metabolic functions.

Cells require oxygen. Oxygen and blood flow are required to keep the body functioning. Increased blood flow increases pulse and pressure. The respiration of the lungs is important for bringing oxygen throughout the body.

Data will be recorded from three activities, eating, stretching/bending, and jumping jacks. It is expected that the metabolic rates will increase with increase in activity.

Analysis of Data: Results of the data collected from the activities showed increase in metabolic rates for certain activities. The activities of stretching and jumping jacks matched the initial hypothesis in the expectation of increases in metabolic rate.

Some data that did not correspond with the hypothesis. The largest variance between the baseline readings and the first activity of eating appears in the systolic measurement. The data gathered from the activity of eating resulted in a decrease in the measurement of systolic blood pressure and only a slight increase in diastolic blood pressure. Respiration for the activity of eating increased just slightly. In gathering the data, some individual measurements of systolic and diastolic rates were lower after eating, surprisingly.

Problems with data:

The systolic readings for activity one seem the most inconsistent. Not sure if it is due to technique or if reading was taken inaccurately. If reading is accurate would eating which involves digestion reduce systolic blood pressure?

Conclusion:

During activity the heart needs to pump faster to get the flow of blood to the body parts and the need for oxygen during activity would raise metabolic rates. The data for activities 2 and 3 support the hypothesis. However, activity 1 did not support the theory because of the decrease in systolic bp.

Blood Pressure Lab

2008-10-13T21:20:00.000-07:00

State a problem about the relationship of age and gender to blood pressure.

Blood pressure tends to rise with age and males traditionally had higher blood pressure.

Use your knowledge about the heart and the circulatory system to make a hypothesis about how the average blood pressure for a group of people would be affected by manipulating the age and gender of the group members.

We can affect average blood pressure readings by including more women or a younger age group to lower the readings or an older age group to increase the average blood pressure readings.

How will you use the investigation screen to test your hypothesis? What steps will you follow? What data will you record? I'd record the individual blood pressure readings and compare the group averages.

The group of individuals will be categorized by gender and age group. The data recorded would include the systolic and diastolic readings.

Analyze the result of your experiment. Explain any patterns you observed.

For both the male and female groups, the older age group tended to have higher average readings. However there was exceptions. A few of the individuals within the group had higher than average readings that affected the overall average. Also, the female age group between the age of 18-24 appeared to be in better health.

Did the result of your experiment support your hypothesis? Why or why not? Based on your experiment what conclusion can you draw about the relationship of age and gender to group blood pressure averages?

The results did not fully support my hypothesis. Other factors that determine blood pressure averages are health history such as diet and exercise.

During the course of your experiment, did you obtain any blood pressure reading that were outside of the normal range for the group being tested? What did you notice on the medical charts for these individuals that might explain their high reading?

A few individual showed higher than average blood pressure. Their medical charts included family history or other factors.

List risk factors associated with the hypertension. Based on your observation, which risk factor do you think is most closely associated with hypertension?

The risk factors include a family history of hypertension, alcohol use, high salt-intake and lack of exercise.

What effect might obesity have on blood pressure? Does obesity alone cause a person to be at risk for high blood pressure? What other factors, in combination with obesity, might increase a person's risk for high blood pressure?

Obesity causes the heart to work harder. In addition the fat or cholesterol that accumulates in the arteries can affect blood pressure causing overweight persons to be at higher risk of having elevated levels of blood pressure In combination with obesity, smoking, drug use, diet, exercise and lifestyle. Too much stress is a contributing factor.

Self and Unit Evaluation

2008-09-23T16:10:00.000-07:00

1. What were the three aspects of the assignments I've submitted that I am most proud of?

Preparation, review, concept. Although I think the final product was not fully representative of these aspects. The course required the pulling together of varied assignments of different formats which I feel was a learning experience in many areas.

2. What two aspects of my submitted assignments do I believe could have used some improvement?

Preparedness, word processing familiarity are the two aspects that detracted from focus in other areas.

3. What do I believe my overall grade should be for this unit?

I think I met the basic requirements. Overall I'd say B.

4. How could I perform better in the next unit?

Being more familiar with the format should give me more of a flow with the material.

   At what moment during this unit did you feel most engaged with the course?

   This was a little surprising to me but it was working with the lab model. For me it more of a relaxed way of approaching the topic.

   At what moment unit did you feel most distanced from the course?
   I was a little overwhelmed in the beginning.

   What action that anyone (teacher or student) took during this unit that find most affirming and helpful?
   Everyone at the learning center was extremely helpful.

   What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing?
   I think it was little difficult starting out because of my own apprehension.

What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.)
   The use of a blog site. The versatility in visual presentation.

2008-09-19T20:25:00.000-07:00

www.foxnews.com

To Grow or Not to Grow

2008-09-19T20:22:00.000-07:00

Can growing of genetically modified crops coexist with non genetically modified crops and what are the potential dangers. Some scientists say that not enough testing has been done and the affects are often cumulative. Biotech corporations suggest that the differences are minimal. However, some in the scientific and environmental community have different conclusion. One such explanation stated that organisms created from gene-splicing are different in their genetic make up and interact to their surroundings differently on a cellular level. The genes behave in a way like a virus. "The foreign gene acts independently of cellular controls, uncorrelated with the other genes".

In reference to controlling contamination "the official advise of the UK is that there should be a separation of 50 meters". There are just as many differing opinions. Certain governments and biotech corporations believe with the proper controls contamination can be minimized. A study made in Mexico discovered GM corn contamination as far as several hundreds of miles. "Mexico doesn't allow genetically modified cultivation" and has concerns over biodiversity and preserving it's "unique strains of maize". Some opponents of genetically modified crops say it should never be allowed to be cultivated on a large scale.

One ecologist provided five reasons why genetically modified crops should not be grown. His issues were consumer choice, potential health risk, the loss of small scale farming, corporate control of food supply, and environmental issues. Regards to consumer choice, some say consumers don't want to eat genetically altered food. One incident that caused alarm was the finding of corn taco shells that contained genetically altered corn made for livestock. The proponents of engineered foods believe it is safe, but many scientists, environmental activists, and some farmers think more studies should be done. The risks are said to be allergic reactions. "Genetic modification frequently use proteins from organisms that have never before been an integral part of the human food chain". Antibiotic resistance can also occur because of the alteration. And the threat of cross pollination. Genetically modified crops are often dominant and there is a concern of pharmaceutically altered crop contaminating non-gentically modified crop as in Texas when a vaccine for pigs with a stomach disease was mixed. In some studies the use of modified crops required more pesticide and herbicide use that traditional crops. In effect some crops because of their genetic characteristics become more like weeds. The reduction of biodiversity, greater use of pesticides and herbicides is a concern among environmentalist. In years we've see the reduction of small scale farming. If the crops require harsher pesticides due to their resistance this can impact our ecosystem. In some tests the "pest resistant crops failed to deliver". Because genetically modified crops share different evolutionary paths when introduced into an environment it can contaminate the existing plants. Growing modified crops require that the seeds be purchased from the biotech company that supplies them and often times the cost is greater than conventional seeds with the hope of a greater yield. The proponents against genetically modified crops seem to say that the dangers outweigh any of the benefits

I think it is a difficult issue, and the topic is broader than it suggests. I tend to agree that there are too many ways for contamination to occur. The long term effects are not yet known. I do agree that it's worth looking into more because it deals with areas of health on an individual and global scale and the sustainability of food supply and the food chain is also linked to our ecology. I can see the concern, alterations on a cellular level comprises many variables.

Reference:

http://www.bio-intergrity.org/health-risks/health-risks-ge-foods.htm

http://online.sfsu.edu/~rone/GEessays/WhatisGE.html

2008-09-18T19:45:00.008-07:00

Dragon-Punnett Square Lab

2008-09-18T19:45:00.007-07:00

Meiosis division results in daughter cells that are not identical and the resulting offspring can manifest different phenotype. Meiosis creates genetic diversity. During fertilization depending on cell makeup the offspring can vary from the parent because of a recessive gene. In the diagram of the dragons genetic makeup the letters can match up but if there is a recessive trait it will show up in the phenotype although the genotype is similar. How the alleles interact affects the appearance of the offspring. The alleles constitute the genotype and the genotype expresses the phenotype.

The Punnett square was developed by R C Punnett an English Biologist. It is used to help determine ways that alleles combine. A cell carries two alleles for each trait. One from the mother and another from the father. Each has two alleles for each trait. A homozygote has two identical alleles and a hetrozygote has two different alleles for a gene. A dominant allele is shown as uppercase letters and the recessive in lowercase letters. Homozygous dominant is a genotype that is shown in the square as LL, homozygous receptive is ll, and hetrozygous is Ll. Dihybrid cross is when two traits are being considered and monohybrid is when one is being considered.

2008-09-18T19:45:00.006-07:00

http;//genome.gsc.riken.go.jp/hgmis/posters/chromosomes/faqs.html

Genetics Compendium

2008-09-18T19:45:00.005-07:00

Early Fetal Development

Fertilization-occurs when a sperm makes it's way through the corona radiata where the acrosomal membrane digests through the zona pellucida and binds to and fuses with the egg's plasma membrane. When the sperm enters the egg, and the sperm nucleus joins with the egg nucleus to form a zygote.

Processes required for development are cleavage when the zygote divides by mitiotic divisions. Each cell has the full amount of chromosones (23 pairs). The mass of cells now called a morula increases in size and the inner cell mass becomes present to become a blastocyst. Identical twins are formed when if the morula splits. Fraternal twins are formed by two separate eggs and sperm.The blastocyst implants in the uterus and is then called an embryo. Embryo experiences growth, increase in size; morphogenisis where the embryo assumes different shapes; and differentiation when the cells start to specialize in function and structure.

Extraembyonic membranes- are outside the embryo and consist of the chorion, the fetal half of the future placenta that gets nourishment from mom, and rids waste from fetus. The allantois develops into placenta arteries, veins, and bladder.The umbilical arteries and veins exchange blood. The yolk sac is where blood cell formation and blood vessels form. And the amnion is the fluid that cushions and protects the fetus from temperature extremes and shock.

Gestation period-is 280 days normally, from start of last menstrual period to the expected date of delivery. It's in the first week of gestation that the blastocyst implants into the uterus, clinically known as pregnancy.

Embryonic development-

2nd week of gestation, HCG is secreted by the chorion and affects the corpus luteum which secretes hormones that ends the menstrual cycle and is also the hormone to determine pregnancy. The inner cell mass becomes an embryonic disc in a process called gastrulation. The yolk sac forms the first sight of blood vessel formation, the amniotic cavity fills with amniotic fluid and the cells of the inner mass differentiate into 3 primary germ layers: ectoderm, mesoderm, and endoderm.

3rd week, nervous system and circulatory system start to develop including the heart

4th and 5th week, the body stalk becomes the future umbilical cord that connects the embryo to the chorion, the future placenta. The allantois becomes the umbilical artery and veins. At this time limb buds appear, the head enlarges: and the eyes, ears, and nose appear.

6th-8th week,embryo starts to resemble a human, reflexes develop.

Fetal developement- After 2 months the embryo becomes a fetus.

3rd-4th month, the head becomes larger in proportion to the rest of the body, and the fingernails, nipples, eyelashes, eyebrows, and hair on the head appear. Cartilage begins to be replaced by bone. Fetal sex can be seen on ultrasound and the heartbeat can be heard with a stethoscope on mom's abdomen.

5th-7th month, movement can be felt, eyelids open. The baby can survive if it is born at the end of this period.

8th-9th month, full term babies have the best chance to survive and premature babies can suffer from respiratory distress syndrome, jaundice, and infections.

Genes/Chromosones in Inheritance

Every cell has 46 chromosomes. a chromosome has two sister chromatids held together by a centromere. Chromosomes are paired, males have XY and females have XX.

The Cell Cycle- consists of interphase, 90percent of the cycle and cell division. There are 3 stages in interphase: G1stage the cell doubles, S stage it replicates. and G2 the cell breaks down proteins for cell division. There are 2 types of cell division, Mitosis and meiosis, and 2 stages mitotic and cytokinesis.

Mitosis-when the parent cell divides into two daughter cells that are identical to the parent cell through the process of prophase, metaphase, anaphase, and telophase.

Meiosis-when cell divides into four daughter cells that are not identical. Spermatogenisis and oogenisis involve meiosis.

Chromosome inheritance-A chromosome carries genetic information in a certain order. When nondisjunction occurs it results in trisomy, 24 chromosomes or monosomy 22 chromosomes. Nondisjunction can result in too many or too few sex chromosomes. Example is Turner Syndrome were only one chromosome is apparent. Certain syndromes can be traced to chromosome structure changes. The kinds of changes include<>

DNA/genes in cell metabolism

DNA is a found in the nucleus of the cell and stores gene information, can replicate, and undergo mutation. It has a double helix and is comprised of a series of nucleotides. The phosphate and sugar molecules are the backbone of the paired bases. Replication occurs creating two identical molecules. RNA are made up of sugar ribose and assists DNA in protein synthesis. Three types of RNA assist in the process: rRNA found in ribosomes, mRNA which act as messengers, and tRNA which tranfers amino acids to ribosomes. Protein synthesis requires transcription when a copy is made and translation that occurs when a codons from MRNA match up to a sequence of amino acids.

Cellular basis for cancer

Cancer develops in various stages and is a cellular disease. The cells replicate divide unlimited times. Cacinogenisis starts with initiation when the cell starts to divide, promotion when the tumor develops, and progression when the cells mutate and starts to invade other cells.

Recombinant DNA- Genetically modified form of DNA created by the insertion of DNA into an "existing organismal genome. A restriction enzyme is used to fuse a human DNA with a plasmid DNA. Another enzyme DNA ligase seals the opening and the rDNA molecule is ready. Bacteria take up the plasmid. when plasmid replicate it becomes a clone. The resulting bacteria can also result in becoming a product.

Cell Compendium

2008-09-18T19:45:00.004-07:00

Cells

Basic Characteristics of Life-

Share common structure of organization

Take materials and energy from the environment

Reproduce

Growth and Development

Interact with environment through stimuli

Evolve

Molecules of Life

Pairing of two or more atoms creates a molecule. When different atoms combine it creates a compound. There are 4 types of organic molecules:

1. Proteins- Composed of amino acids they support structure and functioning of cells. It is within the skin hair and nails such as keratin and collagen. In enzymes they create specific chemical reactions. When in the plasma membrane they help to transport materials in and out of the cell. Hormones and antibodies also consist of proteins. Certain proteins also help in muscle contraction.

2. Carbohydrates- Are sugars that function in the storage and transport of short - term energy.They have a 2:1 ratio of hydrogen to oxygen similar to water. They are the main energy source for the human body. The process of metabolism releases energy. There are 2 types: Simple carbohyrates are called monosaccharides. Examples are fructose,

glucose, galactose. "When humans eat starch, glucose is absorbed into the bloodstream. Once absorbed, the human body distributes glucose to the areas where it is needed for energy".Complex carbohydrates are polysaccharrides consisting of long chain simple sugars.

3. Lipids - Functions in storing of energy, signaling pathways, insulating the body, and forming of cell membrane. A high energy source not water soluble. It includes cholesterol, sterol, glycerides and fatty acids which are neutral and don't carry a charge. Phosholipids are different in molecular structure, having phosphate and nitrogen. They are polar and form the cell membranes. Steroids differ by having 4 fused carbon rings. Testosterone, estrogen, and cortisol are important to reproduction and metabolism.

4. Nucleic Acid - There are 2 types DNA and RNA. DNA stores genetic info and is like a blueprint that contains instructions for the components of cells, proteins, and RNA molecules. The part of The DNA that carries the instruction is the genes. DNA is able to replicate and transmit the information when a cell reproduces. RNA is involved in protein synthesis. Both are polymers and macromolecules which are made of sugar, a base, and phosphate. Sugar deoxyribose is DNA and RNA contains the sugar ribose. DNA has a helix and is double stranded and RNA is single stranded without a helix. ATP is a high energy molecule created when adenine and ribose are changed by a regrouping of three phosphates.

Cell Structure and Function

Cells form the structure of living organisms. The cell is the smallest unit of life capable of exhibiting the basic characteristics of life.

The Cell Theory states that all cells come from other cells, all of life is made of cells, and that cells are the basic unit of life. Cells can be different in shape and function.

The outer shell of the cell is called the plasma membrane it is permeable and regulates what enters and exits the cell. The membrane contains proteins and lipids.Diffusion is a process of molecules equally distributing from high to low areas of concentration. It creates a means for molecules to enter and exit a cell. Osmosis moves water and a solute across the membrane. Facilitated transport is when a protein is used as a carrier to cross the membrane. Diffusion, osmosis, and facilitated transport are "passive" they don't require energy to facilitate movement. Active transport requires cellular energy, a protein carrier and moves from low to high. Endocytosis is a process that takes in substances through the membrane by creating a "pouch" and exocytosis is the process when a "pouch" is formed to release a substance. Within the membrane is a fluid consisting largely of protein called the cytoplasm where various organelles reside.

Cell Organelles and Metabolism

Membraned bodies within the cytoplasm with specific design and functions.

1.Endoplasmic reticulum- channels that connect the nucleus to the cell membrane. There are 2 types, rough and smooth. Rough contains ribosomes and smooth do not.

2.Ribosomes- are attached to the endoplasmic reticulum and where RNA synthesize proteins.

3.Gogli apparatus- flat stacked membranes where sugars are converted to starch or bonded to proteins and lipids.

4.Vesicle-a storage sac that can move between organelles by endocytosis or exocytosis.

5.Lysomes- are found in all cells, contain enzymes that break down macromolecules.

6.Mitochondria- where cellular metabolism occur. Converts glucose into ATP molecules in the process of cellular respiration. Cellular respiration is an important metabolic process that releases energy slowly. The process of converting glucose is called glycolysis.

7.Nucleus-contains DNA information and contained in a double membrane.

Cytoskeleton- its protein meshing maintains the cells shape and buffers organelles. There are 3 different tubules: microtubules,actin filaments, and intermediate filaments. The centrosome organize center of the microtubes. The cilia and flagella are have micotubes in the center. Their protein projections create movement.

Tissue Types

Tissue comprises of cells that are specific to its function. There are 4 types:

Connective Tissue

Fibrous connective tissue are made of fibroblasts that support the internal organs.

Adipose is another connective tissue that stores fat, protects, and insulates.

Dense fibrous connective tissues is in tendins, ligaments and connect muscle to bone.

Supportive connective tissue consisting of cartilage is called hyaline cartilage, elastic cartilage is found in the ear, and fibrocartilage is found in knee joints and vertebrae.

Fluid connective tissue include blood:white blood cells and platelets, and lymph that absorb fluids.

Muscular Tissue

Contain actin and myosin proteins that enable movement.There are 3 types: skeletal muscle which are striated and voluntary with multiple nuclei, smooth muscle can be found along the walls of organs and is involuntary and has a single nuclei, and cardiac muscle which lines the heart is striated and involuntary.

Nervous Tissue

Form a communication network consisting of neurons and neuroglia. Neurons are made of dendrites which receive signals, the cell body, and axon which conducts impulses,

Epithelial Tissue

Forms along the body cavities consisting of tightly packed cells. It is exposed on one side and secured to connective tissue on the other.There are 5 types:

Simple Epithelia

Squamous epithelium has a single layer of cells, found in the lining of the lungs and blood vessels. Cuboidal epithelium also has a single layer and is found in the glands. Columnar epithilium line the digestive tract and oviducts and are columnar in structure.

Pseudostratified Columnar Epithelium line the windpipe and.

Transitional Epithelium can be found lining the urinary bladder and urethra and can change according to tension.

Stratified Epithelium have layer of cells and can be found in the nose moth esophagus and cervix.

Glandular Epithelium secretes a substance to be move to the blood or ducts.

2008-09-18T19:45:00.003-07:00

cellBy Fujoshi on Flickr

www.flickr.com

2008-09-18T12:20:00.005-07:00

Conclusion: the making of the model was challenging and provided a better understanding of the parts that work together and why. The most difficult part was figuring how where the pieces should go.

2008-09-18T12:20:00.004-07:00

Illustrates DNA transciption, tRNA translation and the role of proteins (amino acid chain).

2008-09-18T12:20:00.003-07:00

These are the phases of Mitosis which produce two identical daughter cells.

2008-09-18T12:20:00.002-07:00

Double stranded DNA and it's base pairs

2008-09-18T12:20:00.001-07:00

This model shows the multiple chromosomes in the nucleus.

Lab-Cell Model

2008-09-18T12:20:00.000-07:00

These are the materials used to build my cell model.

Here are the parts of the cell:
cell membrane-the boundary of the cell that contains proteins and lipids
nucleus and nuclear membrane-where the genetic information is stored and the outer sac
endoplasmic reticulm-tubules and sacs where proteins and lipids are synthesized
rough w/ribosomes-where proteins are synthesized
smooth w/ribosomes-where lipids are synthesized
gogli apparatus-flat stacks where sugars convert to starches and or bonded to proteins or lipids
lysomes and vesicle-contains enzymes for digesting macromolecules
mitochondria-facilitates cellular metabolism
Cilia and flagella-projections from cells that create movement

Onion Tip 40x

2008-09-16T22:16:00.000-07:00

The Microscope

2008-09-16T22:03:00.000-07:00

The micoscope consists of:

Stage: The platform where the specimen is placed

Focus Knob: Focusing is adjusted by turning the coarse and fine knobs to bring in or sharpen your image

Iris: It controls the amount of light that comes through the slide

Oculars: These are the lenses that you look through to view your specimen

Objectives: They are the lenses that provide magnification. They rotate on the nosepiece.

Brief History of microscope

.The first microscope was made around 1595. Zacharaias Janssen produced the first compound microscope . The making of the compound microscope advanced the field of Microbiology.It had the magnification of 3x to 9x. Robert Hooke an English Inventor, improved the compound micoscope around 1660 and was credited with "coining the word cork" that he discovered through the microscope. He was also a mathematician and formulated the theory of planetary movement. Anton Van Leeuwenhoek built simple microscopes and is known as the first person to describe bacteria. He was insipred by the readings of Robert Hooke. In 1873 Ernst Leitz introduced objectives that rotated on a nosepiece. And in 1931 Max Knoll and Ernst Ruska introduced the first electron microscope.

Microscope User's Guide

2008-09-11T20:17:00.000-07:00

Mechanical Adjustments

1. Turn the condenser knob all the way up

2. Turn the fine focus knob to mid range

3. Adjust left and right oculars to 64

4. Move blue filter into place

5. Rotate the 4x objective into place

6. Turn on microscope

7. Turn rheostat dial to 10

8. Place specimen on stage and secure stage clips

9. Use XY controls to adjust specimen so light is passing through it (opening the iris provides more light

and makes it easier to line-up the specimen)

10. * REMEMBER* to close the iris, always do this before looking through the oculars.

11. Raise the stage as high as it can go by turning the coarse focus knob clockwise

Viewing Adjustments

12. Adjust the oculars in and out until you see one image

13. Looking through the microscope slowly adjust the coarse focus until image comes into view

14. Use fine focus to create a sharper image

15. Now you can center your specimen by using the XY controls again

16. To view specimen under other objectives 10x, 40x, etc., rotate objective into place and repeat steps: 13,14,15 * As

magnification increases, opening the iris slightly might be helpful.