Human Biology

Why Should Anyone Reproduce?

2008-05-13T05:00:00.000-07:00

Bombarded with the facts of an overabundance of energy use, food stores dwindling, and the over-population of the world, I am not sure if anyone should reproduce. Of course, I already have one biological child and do not feel the great pull to make sure a part of me lives on in the world.

Prices for food and gas skyrocket, disproportionate to the cost of living increasing. I have four children and the price for groceries alone is enough to question why anyone has children anymore. With that in mind, many pregnancies are unwanted and the adoption rate does not come close to helping those in need. The dichotomy of starving and unwanted children in the world to the obese 100 lbs 5 year olds on Jerry Springer disgusts me.

Although I hate to think about regulating the number of children individuals in a society can have, it may be a start to controlling some of the resource depletion that threatens our world. How can we expect to feed and house our growing populations? One possible solution would be one child allowed and you have to pay substantial fees to have more. That seems against the principles of our democratic society though and very elitist.

I hope over time that technology will enhance our ability to save our world and allow for our free standing society in which we have a food surplus, no one starves, the world is is safe from the evils of greenhouse gases and radiation, and the world will become more stable in the economy. But realistically, I cannot see that happening and can only hope that the we can outlast what we have done to the world.

Self Eval

2008-05-13T04:44:00.000-07:00

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

I am just happy to be done at this point even though not everything is turned in. After I got behind from being sick, I did all of unit 3 and 4 since May 6 and I am tired.

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

Everything. I got so behind in my 5 classes that all my work suffered. And I really hate my moving limb. It is ugly. I didn't have time to paint it.

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

Honestly, I have no idea. All of my work is not in and I will be happy if I pass at this point.

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

Not get sick, not have surgery, don't hit every branch of the procrastination tree on the way down even if I have a good reason.

List of Species Lab-Unit 4

2008-05-13T03:15:00.000-07:00

Homo Sapien
My husband
Symbiotic
Domesticated :)

Canis Lupus Familiaris
Dog (4 out of the 6 I have)
Symbiotic
Domesticated

http://www.the-lizard-lounge.com/content/gallery/lizard-pictures/green-anole-pictures/green-anole-01.jpg

Anolis Carolinensis
Green anole (Have 2)
Mutualistic
Not domesticated

http://www.petzoo.co.uk/images/Picture%20667.jpg

Eublepharis Macularis
Leopard Gecko (Have 1)
Mutualistic
Not domesticated

http://jspatel.myweb.uga.edu/images/image007.jpg

Lactobacillus Acidophilus
Yogurt bacteria
Commensal
Domesticated

http://www.lib.uiowa.edu/hardin/md/pictures22/cdc/PHIL_3050_lores.jpg

Trichophyton
Ringworm
Parasitic
Not domesticated

http://millrace.files.wordpress.com/2007/06/blackwidow.jpg

Latrodectus matrans
Black Widow Spider
Predator
Not domesticated

http://www.caminoanimalclinic.com/articles/images/snake07.gif

Crotalus Atrox
Western Diamondback Rattlesnake
Mutualistic
Not domesticated

http://i210.photobucket.com/albums/bb192/shncjj/IMG_2355.jpg

Ocimum Basilicum
Sweet Basil
Mutualistic
Domesticated

http://doreen.mkbmemorial.com/NF/photos/mrsa-nora-2004.jpg

Staphylococcus Aureus
MRSA
Parasitic
Not domesticated

Lavendula Angustifolia
Lavender
Mutualistic
Domesticated

http://www.candbsupplies.ca/roman-chamomile.gif

Chamamelum Nobile
Chamomile
Mutualistic
Domesticated

http://pestcommand.com/wp-content/uploads/2007/12/dust_mite.jpg

Dermatophagoides pteronyssinus
Dust mite
Parasitic
Not domesticated

Cannabis Sativa
Marijuana
Commensal (job security)
Domesticated

http://www.sumivector.com/images/stories/medium/rift-valley-fever_med.jpg

Coccidioides Immitis
Valley Fever
Parasitic
Not domesticated

http://www.nga.gov/feature/sculpturegarden/plantings/summer/images/heliotrope-fs.jpg

Heliotropium arborescens
Heliotrope flower
Mutualistic
Domesticated

http://www.cooperis.com/quizzes/cheese.jpg

Heiphinic Wotis
Cheese
Mutualistic
Domesticated

http://www.herbalextractsplus.com/images/herbs/avocado-bsp.jpg

Persea Americana
Avocado
Mutualistic
Domesticated

http://www.thriftyfun.com/images/articles16/skunk298x300.jpg

Mephitis Mephitis
Skunk
Mutualistic
Not domesticated

http://www.astrographics.com/GalleryPrints/Display/GP2144.jpg

Escherichia Coli
Intestinal bacteria
Symbiotic/Parasitic
Not domesticated

Working Limb Lab Project

2008-05-13T00:38:00.000-07:00

This project highlights the ability to show and understand the concept of a moving limb and the neuron triggering muscle to pull on bone to make a joint move. I chose the joint between the humerus and the ulna and radius at the elbow.

Limb construct equipment

I began the initial project with:

Humerus: wide piece of trim
Radius: wood piece
Ulna: wood piece
Bicep brachii and tricep brachii: rubberbands (anchored with push pins)
Elbow joint: hinge and screws

Beginning of the elbow joint

Bicep brachii (contracted) across humerus to radius

Tricep brachii (contracted) across humerus to ulna

Humerus

Ulna and Radius

I recycled some of my cell from unit one to show a muscle fiber:

Sarcolemma: purple ribbon
Myofibril: groups of dark pink beads
Mitochondria: light pink beads
Sarcoplasm: white styrofoam

Muscle fiber

A muscle fiber slides by contraction and relaxation. When the myofibrils contract, the sacromeres shorten. Thick filaments are composed of several hundred molecules of myosin, which end in a cross bridge on the globular head. Thin filaments are primarily 2 intertwining strands of the protein actin. 2 other proteins, troponin and tropomyosin, play a role. When muscles are stimulated, impulses travel down a T tubule and calcium is released from the sarcoplasmic reticulum. ATP supplies the energy for the muscle contraction. Calcium binds to tronoponin, exposing mysoin receptor sites. Myosin then uses ATP to pull actin toward the center of the sarcomere.

Sarcomeres relaxed

Calcium binds to tronoponin, exposing mysoin receptor sites. Myosin then uses ATP to pull actin toward the center of the sarcomere.

Calcium binds to troponin, exposing myosin receptor sites.

Sarcomeres contract after myosin utilizes ATP to pull actin toward center of sarcomere

I learned a great deal in this lab regarding limb and muscle movement. The chemical reactions that take place on the microscopic level allow for the movement that we can see at a much larger level.

Leeches - Online Lab

2008-05-12T23:04:00.000-07:00

This lab simulates dissection and simulation of neuron activity in a leech.

1. What is the electrode measuring?

The electrode is measuring the voltage of individual neurons.

2. Why use leeches in neurophysiology experiments?

Leeches have large, easily accessible neurons in their nerve cord.

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

A sensory neuron takes nerve impulses from a sensory receptor to the CNS. A motor neuron takes nerve impulses away from the CNS to an effector.

4. Do you think a leech experiences pain? What is pain?

I think a leech experiences pain. Pain is a response from the damage of tissues carried through the neurons by neurotransmitters.

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

Me trying to overcome my computer illiteracy and I actually thought the background information on the leeches was extremely interesting.

6. Anything you found confusing or didn't like about the lab?

Only my computer and procrastination as usual. You think I would learn, even if I have a good excuse.

Compendium Review: Reproductive System and Development and Aging

2008-05-12T13:40:00.000-07:00

Reproductive System

Table of Contents

Human Life Cycle
Male Reproductive System
Female Reproductive System
Female Hormone Levels
Control of Reproduction
Sexually Transmitted Diseases

Human Life Cycle

The reproductive cycle in males and females differs greatly. Sexual maturity in females occurs between the ages of 11-13 and in males from 14-16. DNA is distributed among 46 chromosomes within the nucleus. Mitosis (duplication division) occurs in cells other than reproductive cells. The reproductive system uses mitosis (reduction division). Each reproductive cell contains 23 chromosomes rather than 46 in other cells.

http://courses.bio.psu.edu/fall2005/biol110/tutorials/tutorial2_files/fig_13_3.jpg

Male Reproductive System

The male reproductive system includes the following: testes, epididymides, vasa deferentia, seminal vesicles, prostate gland, urethra, bulbourethral, and the penis.

http://www.drstandley.com/images/male.gif

http://www.mhhe.com/socscience/sex/common/ibank/ibank/0053.jpg

The penis is the male organ of sexual intercourse. The penis has a long shaft and an enlarged tip called the glans penis, which at birth is covered by a layer of skin. Circumcision is the surgical removal of the penis foreskin.

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/10223.jpg

Spongy, erectile tissue containing distensible blood spaces extends through the shaft of the penis. During arousal, autonomic nerves release nitric oxide (NO) This leads to the production of cGMP which causes the smooth muscle of incoming arterial walls to relax and the erectile tissue to fill with blood. The veins that take blood away from the penis are compressed and the penis becomes erect.

http://www.mhhe.com/socscience/sex/common/ibank/ibank/0045.jpg

The testes produce sperm and the male sex hormones. They lie outside the abdominal cavity within the scrotum. The seminiferous tubules are packed with cells undergoing spermatogenesis (production of sperm). Mature sperm has 3 distinct parts: a head, middle piece, and tail. Mitochondria in the middle piece provide energy for the tail movement.

http://www.ehponline.org/members/2006/114-11/sperm.jpg

Sex cells reproduce with meiosis as opposed to mitosis. Spermatogenesis occurs as follows:

http://umanitoba.ca/science/biological_sciences/lab14/images/Spermatogenesis.jpg

The hypothalamus has ultimate control of the testes' sexual function because it secretes a hormone called gonadotropin-releasing hormone (GnRH). There are 2 gonadotropic hormones: follicle-stimulating (FSH) and luteinizing hormone (LH), which are present in both males and females. In males, FSH promotes the production of sperm in the seminiferous tubules. LH controls the production of testosterone. Testosterone is the main sex hormone and essential for the normal development and functioning of the male organs.

http://www.dva.gov.au/health/menshealth/images/04_hormones.gif

Female Reproductive System

The female reproductive system includes the ovaries, oviducts, uterus, cervix, and vagina.

http://cache.eb.com/eb/image?id=55703&rendTypeId=4

The ovaries release one egg a month and fertilization occurs in the oviduct. Development occurs in the uterus. The vagina is the birth canal as well as the organ for sexual intercourse and outlet for menstrual flow. Development of the embryo and fetus takes place in the uterus.

The external organs of the female are known collectively as the vulva.

http://faculty.southwest.tn.edu/rburkett/repro_12.jpg

Upon sexual stimulation, the labia minora, the vaginal wall, and the clitoris become engorged with blood. The breasts also swell and the nipples become erect. The labia majora enlarge, redden, and spread away from the vaginal opening. Orgasm occurs the height of sexual response. Unlike males, females have no refractory period and can have multiple orgasms in a single sexual experience.

Female Hormone Levels

Female hormone levels cycle on a monthly basis and the ovarian cycle drives the uterine cycle. An ovary contains many follicles and each one contains an immature egg, called an oocyte. A female is born with as many as 2 million follicles, but is reduced to 300,000-400,000 by puberty. During oogenesis, a single follicle actually goes through all stages in one place within the ovary. As the follicle matures, layers of follicel cells surround a secondary oocyte. Eventually, the mature follicle ruptures, the secondary oocyte is released. The follicle then becomes the corpus luteum which eventually disintegrates.

http://www.tarleton.edu/~anatomy/oogenesis.jpg

The ovarian cycle:

http://scienceblogs.com/pharyngula/upload/2006/04/cycle_lg.jpg

Estrogen and progesterone affect not only the uterus, but other parts of the body as well. Estrogen is largely responsible for secondary sex characteristics in females. Menopause is a period in a woman's life where the ovarian cycle ceases. This occurs around 45-55 years of age.

Estrogen and progesterone have other functions, one affecting the endometrium causing the uterus to undergo a cyclical series of events known as the uterine cycle:

http://www.tarleton.edu/~anatomy/folliclecycle.jpg

Following unprotected sexual intercourse, many sperm will most likely make their way into the oviduct, where the egg is located following ovulation. Only one sperm fertilizes the egg and it becomes a zygote, which begins development as it travels down the oviduct to the uterus. The endometrium is now prepared to receive the developing embryo.

http://www.jillstanek.com/archives/fertilization.jpg

Control of Reproduction

Several methods are available to both dampen and enhance our reproductive potential. Birth control methods are used to regulate the number of children an individual or couple will have. Abstinence is the most reliable form of birth control and also prevents the transmission of STD's.
Other methods of birth control are as follows:

http://www.femcap.com/images/birth_control_methods.jpg

http://www.plannedparenthood.org/mar-monte/images/Mar%20Monte/bc_methods_english.gif

Sterilization is a surgical option that is relatively permanent as the success rate of fertility after reconnection is 50%.

Infertility is the failure of a couple to achieve pregnancy after one year of regular, unprotected intercourse. The most common cause of infertility in males is low sperm count and/or a large proportion of abnormal sperm. In women, body weight is the largest factor. The higher the weight, the less of a chance of conception.

Assisted reproductive technologies are available for infertile couples:

Artificial Insemination by donor
In Vitro Fertilization
Gamete Intrafallopian Transfer
Surrogate mothers
Intracytoplasmic Sperm Injection

Sexually Transmitted Diseases

Sexually transmitted diseases are caused by viruses, bacteria, protists, fungi, and animals.

http://www.anselm.edu/homepage/jpitocch/genbio/stds.JPG

Genital human papillomavirus (HPV) is the most common sexually transmitted infection (STI). The virus infects the skin and mucous membranes. There are more than 40 HPV types that can infect the genital areas of men and women, including the skin of the penis, vulva (area outside the vagina), and anus, and the linings of the vagina, cervix, and rectum. You cannot see HPV. Most people who become infected with HPV do not even know they have it.

Development and Aging

Table of Contents

Fertilization
Pre-embryonic and Embryonic Development
Fetal Development
Pregnancy and Birth
Development After Birth

Fertilization

Fertilization is the union of a sperm and egg to a zygote. The acrosome of a sperm releases enzymes that digest a pathway for the sperm through the zona pellucida. The sperm nucleus enters the egg and fuses with the egg nucleus.

http://www.chariho.k12.ri.us/cms/library/images/reproduction/fertilization3.jpg

Pre-embryonic and Embryonic Development

Cleavage, growth, morphogenesis, and differentiation are the processes of development.

The extraembryonic membranes are not part of the embryo and fetus; instead they are outside the embryo. The extraembryonic membranes have the following functions:

Chorion: develops into the fetal half of the placenta
Allantois: accumulates the small amount of urine produced by fetal kidneys
Yolk Sac: first embryonic membrane to appear which contains blood vessels
Amnion: enlarges as the fetus enlarges and contains cushion to protect the embryo

http://img.tfd.com/dorland/thumbs/amnion.jpg

Development encompasses the events from fertilization to birth. Pre-embryonic development encompasses the events from the first week.

http://www.mhhe.com/biosci/esp/2002_general/Esp/folder_structure/re/m2/s2/assets/images/rem2s2_1.jpg

Embryonic development begins with the second week and lasts until the end of the second month. During implantation, the chorion secretes enzymes to digest away some of the tissue and blood vessels of the endometruim and uterus and begins to secrete human chorionic gonadotropin. The start of the major event called gastrulation turns the inner cell mass into the embryonic disk.

Fetal development begins in the third month and the uterus is the size of a grapefruit.

http://www.cerebralpalsychildren.com/CP1.jpg

	One Month Your baby is an embryo consisting of two layers of cells from which all her organs and body parts will develop. 4 weeks 5 weeks 6 weeks 7 weeks
	Two Months Your baby is now about the size of a kidney bean and is constantly moving. He has distinct, slightly webbed fingers. 8 weeks 9 weeks 10 weeks 11 weeks 12 weeks
	Three Months By now your baby is about 3 inches long and weighs nearly an ounce. Her tiny, unique fingerprints are now in place. 13 weeks 14 weeks 15 weeks 16 weeks
	Four Months Your baby is now about 5 inches long and weighs 5 ounces. His skeleton is starting to harden from rubbery cartilage to bone. 17 weeks 18 weeks 19 weeks 20 weeks
	Five Months Eyebrows and eyelids are now in place. Your baby would now be more than 10 inches long if you stretched out her legs. 21 weeks 22 weeks 23 weeks 24 weeks
	Six Months Your baby weighs about a pound and a half. His wrinkled skin is starting to smooth out as he puts on baby fat. 25 weeks 26 weeks 27 weeks 28 weeks 29 weeks
	Seven Months By now, your baby weighs about 3 pounds and is more than 15 inches long. She can open and close her eyes and follow a light. 30 weeks 31 weeks 32 weeks 33 weeks
	Eight Months Your baby now weighs about 4 3/4 pounds. His layers of fat are filling him out, making him rounder, and his lungs are well developed. 34 weeks 35 weeks 36 weeks 37 weeks
	Nine Months The average baby is more than 19 inches long and weighs nearly 7 pounds now, but babies vary widely in size at this stage 38 weeks 39 weeks 40 weeks 41 weeks

Development of Male and Female Genitals

The sex of an individual is determined at the moment of fertilization. Males have a pair of chromosomes designated XY and females have XX. During the first several weeks of development, it is impossible to tell the gender of an unborn child by external inspection.

http://www.mfi.ku.dk/PPaulev/chapter29/images/29-1.jpg

http://www.mhhe.com/socscience/sex/common/ibank/ibank/0058b.jpg

Sometimes, abnormalities in genital development occur. Some XY indivisuals develop into females and some XX individuals develop into males. In androgen insensitivity syndrome, the 3 types of hormones are produced by testes, but the individual develops as a female because the plasma membrane receptors for testosterone are ineffective. True gonadal hermaphroditism in which a person has both ovarian and testicular tissue is rare. However, about 1% of the population has psuedohermaproditism. The individual has testes, but appears to be a normal female until puberty.

Pregnancy and Birth

Major changes take place in the mother's body during pregnancy: energy levels fluctuate, the uterus relaxes, the pulmonary values increase, possible stress incontinence, edema, varicose veins, and of course, stretch marks. The uterus has contractions throughout the pregnancy. False labor contractions are called Braxton-Hicks contractions. Labor has 3 stages.

http://www.stewwebb.com/Amanda%20Birth.jpg

Development After Birth

Development does not cease once birth has occurred. Aging encompasses the progressive changes that contribute to an increased risk of infirmity, disease, and death. There are many hypotheses regarding aging: genetic, a whole body process, and/or other extrinsic factors. Aging affects our body systems in different ways: less elasticity in the skin, collagen fibers decrease, fewer sweat glands, fewer hair follicles, cardiovascular disorders, respiratory disorders, lower blood supply to various organs, constipation, heart burn, gastritis, cancer, neuron death due to a lack of O2 from reduced blood flow, loss of skeletal muscle mass, decline in bone density, arthritis, and hormone level decrease.

http://www.forpeaceofmind.com.au/Vol7/media/images/special_features-medicine_mismanagement-2.jpg

References:

Human Reproduction. (2008). www.biology.iupui.edu/biocourses/n100/2k4ch39repronotes.html

Mader, S. (2008). Reproductive System and Development and Aging. Human Biology 10th Ed. (p 319-352)

Sexual Development. (2008). www.themediaproject.com/facts/development/lifecycle.htm

Reproduction-Online Lab

2008-05-12T11:00:00.000-07:00

The most important step to begin the reproductive cycle (after intercourse) is fertilization. Fertilization begins when a sperm penetrates an oocyte. Sperm live for about 48 hours and fertilization takes about 24 hours. Only 1% of the sperm in the vaginal canal make it to the uterus. The fusion of the oocyte and sperm nuclei marks the creation of the zygote and the end of fertilization.

1 day post ovulation

http://assets.babycenter.com/i/m/fetal/2.jpg

Cellular division begins and after a few weeks, the embryo elongates and expands the yolk sac.
The division continues and at about 9 weeks, the essential body parts are accounted for and the heart finishes division into four chambers.

9 weeks

http://assets.babycenter.com/i/m/fetal/9.jpg

The first trimester ends at about 12 weeks. During this time, reflexes develop. Nerve cells are multiplying and synapses are forming furiously. At week 14, fetal sexual organs are visible, so you can now concentrate on boy or girl names and buying all sorts of color coordinated expensive baby belongings :)

14 weeks

http://assets.babycenter.com/i/m/fetal/14.jpg

At 20 weeks, bone marrow starts making blood cells and the mother can detect fetal movement.

20 weeks

http://www.babycenter.com/i/m/stages/popups/20/index.jpg

At 22 weeks, hearing is possible and during week 23, sensory brain waves activate the auditory and visual systems and blood vessel development begins in the lungs to prepare for life outside the uterus.

23 weeks

http://assets.babycenter.com/i/m/fetal/23.jpg

At week 26, the lungs are capable of breathing air. Testes in the male also descend into the scrotum.

26 weeks

At 32 weeks, the immune system begins to develop. With the plethora of problems that both an under-active and over-active immune system can cause, this step is particularly important.

32 weeks

http://www.babycenter.com/i/m/stages/popups/32/index.jpg

At 36 weeks, the orienting response is prevalent. Ossification of the bones begins and the leg bone is completely ossified. At the end of this week, a fetus is considered full-term.

36 weeks

http://www.babycenter.com/i/m/stages/ultrasound/ultrasound_36_hg.jpg

At 38 weeks, the organs are fully developed for life outside the womb. Lungs increase production of surfactant to keep alveoli open.

38 weeks

http://www.babycenter.com/i/m/stages/popups/38/index.jpg

At 40 weeks, the fetus is full term and birth is imminent. The fetus has over 300 bones, which will later fuse to the 206 bones of an adult.

http://www.channel4.com/health/microsites/M/miracles_in_the_womb/images/feature1.jpg

Is Exercise Enough? Obviously not...

2008-05-12T04:10:00.000-07:00

You know there is a problem in this country when even our pets are fat. We live in a society abundant with food, fat, sugar, and lethargy. There doesn't seem to be a happy medium either...you are either obese or anorexic. Schools try and make up the difference with a quarter or semester of gym and Domino's Pizza. Many parents don't teach their children healthy eating choices and the media bombards us with fast food, sweet treats, sexy bodies, miracle diets, and exercise equipment for the rest of us to work off all the fat.

I think a bigger concern should be a focus on a healthy lifestyle and exercise habits for everyone, not just obese people. Everywhere we turn, the media tells us how we should dress, what to wear, how to look and what kind of body is perfect. Many young women starve themselves to look like a super-model, only to find themselves just as unhealthy (if not worse) than many overweight people.

Having fought with my weight for quite a bit of my life, I have found that regardless of how well I eat, I have never lost weight without some kind of exercise. I was heavy when I was younger until I discovered sports. After that, I ate whatever I wanted, whenever I wanted, without any problem. Finding sports was almost a religious experience. However, I never understood how poorly I ate.

I gained about 100 lbs when I was pregnant when I was 17. I was depressed and unhappy for quite sometime and I didn't even want to leave the house. Although I exercised, it was not nearly to the level I used to, and my eating habits were not even close to healthy. After a few years, I became so obsessed with my weight that I made myself so sick I ended up having a miscarriage when I did not even know I was pregnant. I exercised to the point I put myself in the hospital, I counted every fat gram I ate and weighed myself countless times a day. I worked security at a forklift plant that had 3 forklift scales and I started weighing myself 3 times an hour on each scale and averaging my weight over an eight or ten hour shift.

I also worked nights at the security plant by myself. I started walking more than just my regular security rounds. I tried to end up 1 pound lighter every night I went to work. I started walking 2 miles a night, then 3,4,5...I kept walking until sometimes I would walk 25 miles during a 10 hour shift. I felt so much pressure to lose weight, and of course people noticed, that I kept pushing myself past the point any semblance of a healthy life style. It took sometime to come to a balance of healthy exercise and proper nutrition.

Young adults are not given many of the proper tools regarding nutrition, exercise, and positive body image by their parents or during the educational process. More so than exercise or healthy eating alone, we need to impart that a balance of eating healthy and exercise are a choice that leads to a healthier and happier lifestyle.

How Do Muscles Work? Online lab

2008-05-12T01:16:00.000-07:00

This lab highlights the importance of muscle function, contraction, and the ability of the muscle when stressors are present.

Muscle Action:

Muscles contract when in use and their length and circumference changes dependent on contraction or relaxation. For example, when you flex your bicep (bicep brachii), the circumference is greater and the muscle itself is shorter; the opposite occurs during relaxation.

http://www.arn.org/docs/glicksman/090104%20fig1biceps.jpg

Stressors affect the ability of muscles to properly function. One such stressor is coldness.

http://www.coolantarctica.com/gallery/scenic/Seaice%20formation/Antarctica_sea_ice_forming2.jpg

For this experiment, I made a certain number of fists in room temperature and shortly thereafter, a certain number number after submerging my hand in ice water for 60 seconds.

http://www.holidaycityflash.com/article%20pix/frostbite.jpg

Ok, maybe a bit dramatic for 60 seconds in ice water, although I almost felt ready for the Polar Bear Club!

Temperature	Number of Fists
Normal	45
Ice Water	30

The cold definitely affected my ability to make a fist. The muscles were sluggish and tired, however, once the cold wore off toward the end, I felt like the fist were a little quicker. In the next experiment, I will test muscle strain under the stressor fatigue by squeezing a rubber ball a certain number of times within 20 seconds, 10 times.

Trial	Number of Squeezes
1	38
2	36
3	32
4	32
5	28
6	24
7	22
8	20
9	18
10	16

Over the course of the repetitions, my strength definitely diminished! Not to mention that is not a common, repetitive movement that is utilized day in and day out.

Conclusion:

Stressors such as cold and fatigue do affect muscles of the human body. Some of the process may be due to possible vasoconstriction and lack of blood flow from cold, along with the body beginning to focus on internal organs as opposed to the extremities. Fatigue possibly utilizes the supply of stored muscle energy at much higher rate with nothing left to replenish the depleted chemicals.

Compendium Review: Skeletal System and Muscular System

2008-05-08T08:35:00.000-07:00

Skeletal System

Table of Contents:

Overview of Skeletal System
Bone Growth, Remodeling, and Repair
Bones of the Axial System
Bones of the Appendicular Skeleton
Articulations

Overview of the Skeletal System

The skeletal system consists of 206 bones in and adult, along with the cartilage and fibrous connective tissue which occurs in the ligaments in the joints. The skeleton supports the body, protects soft body parts, produces blood cells, stores minerals and fat, and along with muscle, permits flexible body movement.

http://biology.clc.uc.edu/graphics/bio105/skeleton.jpg

The shaft, or main portion of a long bone, is called the diaphysis. The diaphysis has a large medullary cavity, whose walls are composed of compact bone, lined with endosteum, and filled with yellow bone marrow. The expanded region at the end of a long bone is the epipysis and is composed largely of spongy bone that contains red bone marrow. The epiphyses are coated with articular cartilage. Except for the articular cartilage, a long bone is covered with periosteum (a layer of fibrous connective tissue.)

http://www.web-books.com/eLibrary/Medicine/Physiology/Skeletal/long_bone.jpg

Compact bone is highly organized and composed of tubular units called osteons. Bone cells called osteocytes lie in lacunae which are tiny chambers arranged in concentric circles around a central canal. Spongy bone has a much less organized appearance and contains thin plates called trabeculae separated by unequal spaces. Spongy bone is lighter than compact bone, but designed for strength. The spaces of spongy bone are filled with red marrow.

http://www.web-books.com/eLibrary/Medicine/Physiology/Skeletal/compact_spongy_bone.jpg

Cartilage is not as strong as bone, but is more flexible because the gel-like matrix contains collagenous and elastic fibers. The cells, chondrocytes, are irregularly grouped. There are 3 types of cartilage: hyaline, fibrocartilage, and elastic cartilage.

http://washington.uwc.edu/about/faculty/schaefer_w/TISSUES/hyaline_cartilage1.jpg

Fibrous connective tissue contains rows of cells called fibroblasts separated by bundles of collagenous fibers. This tissue makes up the ligaments that connect bone to bone and the tendons that connect muscles to a bone joint.

http://www.bweems.com/gctenmp1.jpg

Bone Growth, Remodeling and Repair

Bones are composed of living tissues as exemplified by their ability to grow, remodel and repair. Several types of cells are involved in bone growth:

Osteoblasts: bone forming cells that secrete the organic matrix of bone
Osteocytes: mature bone derived from osteoblasts
Osteoclasts: bone absorbing cells that break down bone and assist in depositing calcium and phosphate in blood

The term ossification refers to the formation of bone. The bones of the skeleton form during embryonic development in 2 distinctive ways:

Intramembranous ossification: bones develop between sheets of fibrous connective tissue and cells derived from connevtive tissue cells become osteoblasts, which form spongy bone
Endochondrial ossification: bones replace the cartilaginous models of the bone; gradually the cartilage is replaced by calcified bone

When the epiphyseal plates close, bone length can no longer occur. Growth hormone (GH) stimulates growth of the epiphyseal plates, as well as bone growth in general. Too much or too little GH produces gigantism or dwarfism, respectively.

http://www.gigantism.com/robert-wadlow.jpg

As much as 18% of bone is recycles each year by osteoclasts. Bone recycling allows the body to regulate the amount of calcium in the blood. 2 hormones in particular are involved in regulating the blood calcium level: parathyroid hormone (PTH) and calcitonin. Bone remodeling also accounts why bones can respond to stress. If you engage in an activity that calls upon the use of a particular bone, it will enlarge in diameter at the region most affected by the activity.

http://www.nature.com/ncprheum/journal/v2/n10/images/ncprheum0298-f1.jpg

Repair of a bone is required after it breaks or fractures. Fracture repair takes place over a span of several months in a series of 4 steps:

Hematoma
Fibrocartilaginous callus
Bony callus
Remodeling

The naming of a fracture tells you what kind of break occurred:

http://images.medicinenet.com/images/illustrations/typical_fractures.jpg

Bones of the Axial Skeleton

The 206 bones of the skeleton are classified according to whether they occur in the axial skeleton or the appendicular skeleton. The axial skeleton lies in the midline of the body and consists of the skull, hyoid bone, vertebral column, and the rib cage.

The skull is formed by the cranium and the facial bones. The cranium protects the brain and in adults is composed of 8 bones fitted tightly together. In newborns, certain cranial bones are not completely formed and are joined by membranous regions called fontanels.

http://www.aafp.org/afp/20030615/2547_f1.gif

The most prominent facial bones are the mandible, the maxillae, the zygomatic bones, and the nasal bones. The mandible (lower jaw) is the only movable portion of the skull and its action permits chewing. The lips and cheeks have a core of skeletal muscle. The zygomatic bones are the cheekbones prominences and the nasal bones. Other bones are part of the nasal septum which divides the interior of the nose into 2 cavities.

http://training.seer.cancer.gov/module_anatomy/popup_illustrations/images/illu_facial_bones.jpg

The hyoid bone is not part of the skull, however it part of the axial skeleton. It is the only bone in the body that does not articulate with another bone. It is attached to the temporal bones by by muscles and ligaments and to the larynx by a membrane. The hyoid bone anchors the tongue.

http://www.yorku.ca/earmstro/journey/images/larynx.gif

The vertebral column consists of 33 vertebrae. Normally, the vertebral column has 4 curvatures that provide more resilience and strength for an upright position. The spinal cord passes through the vertebral canal and gives off spinal nerves at the intervertebral foramina.

http://www.univie.ac.at/cga/courses/be524/spinal/spine2-BB.jpg

The rib cage is also called the thoracic cage and is composed of the thoracic vertebrae, the ribs and their associated cartilages, and the sternum. A rib is a flattened bone that originates at the thoracic vertebrae and proceeds toward the anterior thoracic wall. There are 12 pairs of ribs. The sternum lies in the midline of the body and helps protect the heart and lungs. The sternum is composed of 3 bones: the manubrium, the body, and the xiphoid process.

http://www.daviddarling.info/images/rib-cage.jpg

Bones of the Appendicular Skeleton

http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f8-1a_appendicular_skel_c.jpg

Articulations

Bones are joined at the joints, which are classified as fibrous, cartilaginous, or synovial. Some joint are fibrous and immovable. Cartilaginous joints are connected by hyaline cartilage.

A synovial joint is a joint having a cavity filled with synovial fluid. Synovial joints allow for the movements of flexion, extension, adduction, abduction, rotation, circumduction, inversion and eversion.

http://www.palaeos.com/Vertebrates/Lists/Glossary/Images/SynovialJoint.jpg

Muscular System

Table of Contents:

Overview of Muscular System
Skeletal Muscle Fiber Contraction
Whole Muscle Contraction
Muscular Disorders
Homeostasis

Overview of Muscular System

Humans have 3 types of muscle tissue: smooth, cardiac, and skeletal. The cells of these tissues are called muscle fibers. Smooth muscle fibers are spindle shaped cells, each with a single nucleus. The cells are arranged in parallel lines forming sheets. Striations are seen in cardiac and skeletal, but not in smooth. Smooth muscle is located in the walls of hollow internal organs and it causes the walls to contract. It does not fatigue easily.

http://www.arunnersplace.co.uk/images/smooth.jpg

Cardiac muscle forms the heart wall. Its fibers are generally uninucleated, striated, tubular, and branched, which allows the fibers to interlock at intercalated disks.

http://webanatomy.net/histology/cardiac/cardiac_muscle.jpg

Skeletal muscle fibers are tubular, multinucleated, and striated. Skeletal muscles have numerous functions:

Skeletal muscles support the body
Skeletal muscles make bones move
Skeletal muscles help maintain a constant body temperature
Skeletal muscles contraction assists movement in cardiovascular and lymphatic vessels
Skeletal muscles help protect internal organs and stabilize joints

Skeletal muscles are well organized. A whole muscle contains bundles of skeletal muscle fibers called fascicles. Fascia is a type of connective tissue that extends beyond the muscle and becomes its tendon. Tendons quite often extend past a joint before anchoring a muscle to bone.
Skeletal muscles usually function in groups and the nervous system stimulates the appropriate group of muscles.

http://people.uleth.ca/~little/PE2110/funcanatomy/2front%20muscle.jpg

http://people.uleth.ca/~little/PE2110/funcanatomy/2back%20muscle.jpg

Skeletal Muscle Fiber Contraction

A muscle fiber is a cell containing the usual cellular composition, but special names have been assigned to some of these components. The plasma membrane is called the sarcolemma;the cytoplasm is the sarcoplasm;and the endoplasmic reticulum is the sarcoplasmic reticulum.

http://www.sport-fitness-advisor.com/images/muscle_anatomy.jpg

A muscle fiber divides into even smaller parts. Within each fiber are strands of myofibrils. These long cylindrical structures appear striped due to strands of tiny myofilaments. Myofilaments have two types of protein: actin (thin myofilaments) and myosin (thick myofilaments).

http://www.mhhe.com/biosci/esp/2001_gbio/folder_structure/an/m5/s5/assets/images/anm5s5_1.jpg

Muscle fibers are stimulated to contract by motor neurons whose axons are in nerves. The axon of one motor neuron can stimulate from a few to several muscle fibers of a muscle because each axon has several branches. The entire region is called a neuromuscular junction.

http://www.colorado.edu/intphys/Class/IPHY3430-200/image/figure7m.jpg

Axon terminals contain synaptic vesicles that are filled with the neurotransmitter acetylcholine (ACh). When nerve impulses traveling down a motor neuron, arrive at an axon terminal, the synaptic vesicles release ACh into the synaptic cleft. ACh quickly diffuses across the cleft and binds to receptors on the sarcolemma. 2 other protens are associated with an actin filament: tropomyosin and troponin.

http://www.octc.kctcs.edu/GCaplan/anat/images/Image331.gif

Whole Muscle Contraction

A motor unit is comprised of the nerve fiber and all the muscle fibers it innervates. When a motor unit is stimulated by infrequent electrical impulses, a single contraction occurs that lasts only a fraction of a second. The response is a muscle twitch which is divided into 3 stages: latent, contraction, and relaxation. Muscles use various fuel sources for energy and they have various ways of producing ATP during muscle contraction.

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Creatine.gif

Muscle cells store limited amounts of ATP, but they have 3 ways to acquire more ATP: formation of ATP by the creatine phosphate (CP) pathway, fermentation, and cellular respiration. Some muscle fibers metabolize both aerobically and anaerobically. Fast twitch fibers tend to rely on the CP pathway and fermentation which are anaerobic, slow twitch fibers prefer cellular respiration, which is aerobic.

Muscular Disorders

Muscular disorders are divided into those that are commonly seen and those that are more serious. Spasms are sudden involuntary muscular contractions most often accompanied by pain. Multiple spasms of the skeletal muscles are called convulsions. A strain is caused by the stretching or tearing of a muscle.

Tendinitis is an inflammation of a tendon. Bursitis is inflammation of a bursa, a slippery surface where muscle and tendons glide over. NSAIDs are the most common OTC medications for treating arthritis, bursitis, and tendinitis.

Myalgia and Fibromyalgia refer to achy muscles. Myalgia without a traumatic history is usually from a viral infection.

http://simplefibrocure.com/fibrographics.jpg

Muscular dystrophy is a broad term applied to a group of disorders that are characterized by a progressive degeneration and weakening of the muscles. As muscle fibers die, fat and connective tissue take their place.

http://www.dinf.ne.jp/doc/english/global/david/dwe002/dwe002g/dwe00212g01.gif

Myasthenia gravis is an autoimmune disorder characterized by weakness that affects the muscles of the eyelids, face, neck, and extremities. The immune system produces antibodies that destroy ACh which leads to the impairment of muscle contraction.

http://www.myasthenia.org.au/assets/images/eyes2.jpg

Amyotrophic Lateral Sclerosis (ALS) is better known as Lou Gehrig's disease. ALS sufferers experience gradual loss of the ability to walk, talk, chew, and swallow. Mental ability is not affected. There is no cure.

http://graphics.jsonline.com/graphics/news/img/aug07/als_080307_big.gif

Homeostasis

The muscular and skeletal systems work together to achieve homeostasis. Both systems protect body parts and the soft internal organs. They work together to produce movement. The skeletal system (in conjunction with the endocrine system) performs tasks that are vital for calcium homeostasis and cellular metabolism. The bones contain red bone marrow, which is the site of blood production. White blood cells originate in the red bone marrow and they defend the body against pathogens. Muscles also help maintain body temperature.

References:

Mader, S. (2008). Skeletal System and Muscular System. Human Biology, 10th Ed. (p 207-246)

Muscular System (2008.) www.kumc.edu/instruction/medicine/anatomy/histoweb/muscular/muscular.htm

Skeletal System (2008). www.mnsu.edu/emuseum/biology/humananatomy/skeletal/skeletalsystem.html

Compendium Review: Nervous System and Senses

2008-05-06T13:25:00.000-07:00

Nervous System

Table of Contents:

Overview of the Nervous System
The Central Nervous System
The Limbic System and Higher Mental Functions
The Peripheral Nervous System
Drug Abuse

Overview of the Nervous System:

The nervous system has 2 major divisions: the central nervous system (CNS) which consists of the brain and spinal cord and the peripheral nervous system (PNS) which consists of the nerves.

http://www.invanet.org/pics/central%20nervous%20system.jpg

The nervous system has 3 specific functions:

Receives sensory input
CNS performs integration
CNS generates motor output

Nervous tissue contains 2 types of cells: neurons and neuroglia. Neurons transmit nerve impulses between parts of the nervous system; neuroglia support and nourish neurons.

http://www.readingeagle.com/blog/tullio/archives/neurons.jpg
Neurons are classified according to function: sensory neuron (takes nerve impulses from sensory receptor to CNS), interneuron (receive input from sensory neurons and from other interneurons) , and motor neurons (takes nerve impulses away from the CNS to the effector.)

Neurons vary in appearance, but all of them have 3 parts: a cell body (contains nucleus), dendrites (short extensions that receive signals from sensory output), and an axon (portion of neuron that conducts nerve impulses.)

http://www.neurevolution.net/wp-content/uploads/Synapse.JPG

Many axons are covered by a protective myelin sheath. In the PNS this covering is formed by a type of neuroglia called Schwann cells and in the CNS oligodendrocytes perform this function. The gaps where there is no myelin sheath are called teh nodes of Ranvier.

http://kvhs.nbed.nb.ca/gallant/biology/schwann_myelin.jpg

Nerve impulses convey information within the nervous system. The nerve impulse is studied by using excised axons and a voltmeter to measure voltage, which allows us to measure the potential difference between 2 sides of an axonal membrane.

Resting potential: -65mV (inside of the neuron is more negative than the outside
Action potential: +40 mV (rapid change in polarity across the axonal membrane)

http://cache.eb.com/eb/image?id=54737&rendTypeId=4

Every axon branches into many fine endings, tipped by a small swelling called an axon terminal, which lies very close to either the dendrite or the cell body. Transmission across a synapse is carried out by molecules called neurotransmitters, which are stored in vesicles in the axon terminals.

http://fig.cox.miami.edu/~cmallery/150/neuro/c7.48.1.neurotransmitters.jpg

A single neuron has many dendrites plus the cell body, and all of the can have synapses with many other neurons. Therefore, a neuron is on the receiving end of many signals which can be either excitatory or inhibitory. Neurons integrate these incoming signals. Integration is the summing up of excitatory and inhibitory signals.

http://mcdb.colorado.edu/courses/3280/images/synapse/integration.gif

The Central Nervous System

The spinal cord and the brain make up the CNS. Both are protected by bone and wrapped in a protective membrane known as meninges. The spaces between the meninges are filled with cerebrospinal fluid, which cushions and protects the CNS. The brain has 4 ventricles that serve as a reservoir for cerebrospinal fluid. The CNS is composed of 2 types of nervous tissue: gray matter (contains cell bodies and short non-myelinated fibers) and white matter (contains myelinated axons that run together in bundles called tracts.)

http://www.octc.kctcs.edu/gcaplan/anat/images/Image432.gif

The spinal cord extends from the base of the brain through a large opening in the skull called the foramen magnum and into the vertebrae canal. The spinal nerves project from the cord between the vertebrae. The central canal contains cerebrospinal fluid. The gray matter is centrally located and shaped like the letter H. The white matter occurs in areas around the gray matter.

http://www.laesieworks.com/spinal/pict/SpinalCord.jpg

The spinal cord functions as a means of communication between the brain and the peripheral nerves that leave the cord. The spinal cord is the center for thousands of of reflex arcs. Depending on an injury to the spinal cord, paralysis may occur.

http://www.apparelyzed.com/_images/content/spine/spinenerves.jpg

The human brain has been called the last great frontier of biology. The brain is divided into different sections: the cerebrum, the diencephalon, the cerebellum, and the brain stem.

http://www.ahaf.org/alzdis/about/brain_headBorder.jpg The cerebrum is the largest portion of the human brain and the last center to receive sensory input and carrt out integration. The cerebrum has 2 hemispheres; the left and right. The longitudinal fissure divides the hemispheres. Shallow grooves divide the hemispheres into lobes with each lobe carrying out particular functions:

Frontal lobe: primary motor area
Temporal lobe: primary auditory area
Parietal lobe: primary somatosensory area
Occipital lobe: primary visual area

http://static.howstuffworks.com/gif/adam/images/en/brain-picture.jpg

The cerebral cortex is a thin but highly convoluted outer layer of gray matter that covers the cerebral hemispheres. The cerebral cortex contains over 1 billion cell bodies and is the region of the brain that accounts for sensation, voluntary movement, and all the though processes we associate with consciousness.
Association areas are places where integration occurs.

http://www.princetonbrainandspine.com/photos/brain_anat/brain_areas_illus19a.jpg The diencephalon contains the hypothalamus and the thalamus. The hypothalamus integrates homeostasis by regulating hunger, sleep, thirst, body temperature, and water balance. The thalamus receives all sensory input except for smell. The thalamus also participates in higher mental functions such as memory and emotion. The pineal gland (which secretes melatonin) is located in the diencephalon.

http://kybele.psych.cornell.edu/~edelman/Psych-231/diencephalon.gif
The cerebellum lies under the occipital lobe of the cerebrum and is separated from the brain stem by the 4th ventricle. The cerebellum receives sensory input from the eyes, ears, joints, and muscles about the present position of body parts. It also receives motor output from the cerebral cortex about where the parts should be located.

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/18008.jpg The brain stem contains the midbrain, the pons, and the medulla oblongata. The midbrain acts as a relay station for tracts passing between the cerebrum and the spinal cord or cerebellum. The pons contains bundles of axons traveling between the cerebellum and the rest of the CNS. The medulla oblongata contains a number of reflex centers for regulating heartbeat, breathing, and vasoconstriction. Reticular formation is a complex network of nuclei and fibers that extend the length of the brain stem. The reticular formation os a major component of the reticular activating system (RAS) which receives sensory signals and sends them up to the higher centers, and motor signals which sends it ti the spinal cord.

http://library.thinkquest.org/C005704/media/brain_stem.gif

The Limbic System and Higher Mental Functions

The limbic system is an evolutionary ancient group of linked structures deep within the cerebrum that is a functional grouping rather than an anatomical one. The limbic system blends primitive emotion and higher mental function as a united whole. Two significant systems in the limbic system are the amygdala (causes experiences to have emotional overtone) and the hippocampus (crucial to learning and memory.)

http://universe-review.ca/I10-41-limbic.jpg

The Peripheral Nervous System

The peripheral nervous system (PNS) lies outside the CNS and contains the nerves. Nerves are designated as cranial when they arise from the brain and spinal nerves when they arise from the spinal cord. Nerves take impulses to and from the CNS. Nerves are composed of axons.

http://zenith-designs.com/files/nerves.jpg

Humans have 12 pairs of cranial nerves attached to the brain. They are designated with roman numerals. Some are sensory, some are motor, and some are mixed.

http://can-do.com/uci/ssi2001/title_artcranial.jpg

Spinal nerves emerge in pairs from either side of the spinal cord. The roots of the spinal nerve physically separate the axons of the sensory neurons from the motor neurons. The cell body of a sensory neuron is called a dorsal-root ganglion. A ganglion is a collection of cell bodies outside the CNS.

http://www.infovisual.info/03/img_en/039%20Nervous%20system%20spinal%20nerves.jpg

The PNS has different divisions The somatic system serves the skin, skeletal muscles, and the tendons and includes nerves that take sensory information from the external sensory receptors to the CNS and motor commands away from the CNS to the skeletal muscles. Automatic responses to a stimulus in the somatic system are called reflexes.

http://www.daviddarling.info/images/reflex_arc.jpg

The autonomic nervous system is also in the PNS. The autonomic nervous system regulates the activity of cardiac and smooth muscles and glands. The system is divided into the sympathetic and the parasympathetic systems.

The sympathetic nervous division is important during emergency situations. The "fight or flight" mechanism occurs from this division. It accelerates heartbeat and dilates the bronchi by releasing norepinephrine. The parasympathetic division promotes internal responses associated with relaxation: pupil contraction, food digestion, and slowed heartbeat by releasing acetlycholine.

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/autonomic.gif

Drug Abuse

Drugs alter mood and affect emotional state. Drugs either affect the limbic system or promote or decrease the action of a particular neurotransmitter. Drug abuse occurs when a person takes a drug at an improper dose level or takes an illegal drug and becomes physiologically and/or psychologically dependent on the drug.

Alcohol is a CNS depressant and the most commonly abused drug in the world. Alcohol increases GABA and the release of beta-endorphins. Alcohol crosses the blood-brain barrier causing damage to several tissues. Alcohol dehydrogenase is the liver enzyme that metabolizes alcohol.

http://www.thelivercentre.com.au/development/images/alcohol-Effects.jpg

Nicotine is a CNS stimulant that binds to nicotine receptors in the midbrain. Nicotine works by releasing dopamine and is highly addictive. The newest drug Chantix (varenicline) works by interrupting and blocking the uptake of nicotine from the nicotine receptors in the brain.

http://www.sfn.org/skins/main/images/brainbriefings/nicotine.illus.jpg

Cocaine and methamphetamine are both powerful CNS stimulant drugs. Cocaine and meth are primarily dopamine reuptake inhibitors, but have varying degrees of effect and longevity on the human body. Cocaine and methamphetamine have medicinal uses (cocaine as an anesthetic and vasoconstrictor for eye, nose, ear, and throat surgery and meth for ADHD, obesity, Parkinson's disease, and narcolepsy) but are abused world-wide as an illegal substance. They are both highly addictive.

http://www.deadiversion.usdoj.gov/pubs/brochures/pseudo/images/methuse.jpg

MDMA (3,4,methylenedioxymethamphetamine) or Ecstasy closely mimics methamphetamine, but is actually classified as a hallucinogenic drug because it does cause hallucinations (contrary to the text book.) Methamphetamine primarily causes users to see things from a lack of sleep, or from a psychotic episode from overuse, but does not cause synesthesia (transposing of the senses) as true hallucinogenic substances do. One of the primary symptoms of MDMA is synesthesia.

http://fusionanomaly.net/mdma.jpg

Heroin is derived from the opium poppy plant. It has no medicinal value, but is quickly converted to morphine after delivery to the human body. Morphine itself is a narcotic analgesic (pain killer). Narcotics differ from CNS depressants in that narcotic analgesics lower body temperature, cause pupil constriction, limit the pupillary reaction due to the constriction, and ptosis.

http://drugrecognition.com/images/SmallPupil.jpg

Marijuana is an illegal and impairing substance from the THC (Δ⁹-tetrahydrocannabinol) within the plant. THC belongs to a group of chemicals called cannabinoids. Cannabinoid receptors have been located in the brain. Cannabinoids affect the neurotransmitter anandamide and cause problems with motor skills, perception, memory, and orientation. Although cannabis causes euphoria and relaxation, it raises both blood pressure and pulse rate, causes severe pupil dilation, and reddening of the conjunctiva. Federal law prohibits medicinal marijuana in the US, however 14 states have passed laws allowing medicinal marijuana use. Dr. Robert Melamede has conducted much research on cannabinoids for medical use. The following website has interesting information: http://www.thc-ministry.net/cannabisinfo.htm

http://upload.wikimedia.org/wikipedia/commons/e/e1/Cannabis_sativa.jpg

Senses

Table of Contents

Sensory Receptors and Sensations
Proprioceptors and Cutaneous Receptors
Senses of Taste and Smell
Sense of Vision
Sense of Hearing
Sense of Equilibrium

Sensory Receptors and Sensations
Sensory receptors are dendrites specialized to detect certain types of stimuli. Exteroceptors are sensory receptors that detect stimuli outside the body, such as taste, smell, vision, hearing, and equilibrium. Interoceptors receive stimuli from inside the body.

Chemoreceptors respond to chemical substances in the immediate vicinity and monitor blood pH.
Nociceptors respond to pain and the chemicals released by damaged tissue.
Photoreceptors respond to light energy.
Mechanoreceptors are stimulated by mechanical forces.
Thermoreceptors are stimulated by changes in temperature.

Sensory receptors respond to environmental stimuli by generating nerve impulses. When the nerve impulses arrive at the cerebral cortex, sensation occurs.

http://www.rci.rutgers.edu/~uzwiak/AnatPhys/Blood_Vessels_files/image012.jpg

Proprioceptors and Cutaneous Receptors

Proprioceptors are mechanoceptors involved in reflex actions that maintain muscle tone and thereby the body's equilibrium and posture. Muscle spindles act to increase the degree of muscle contraction and Golgi tendon organs act to decrease it. Cutaneous receptors are contained in the dermis layer of the skin. Cutaneous receptors make the skin sensitive to touch, pressure, pain, and temperature. Three types of cutaneous receptors are sensitive to fine touch, two types of cutaneous receptors are sensitive to pressure. Temperature receptors are simply free nerve endings in the epidermis.

http://www.unmc.edu/Physiology/Mann/pix_5/skin.gif

Nociceptors are pain receptors sensitive to chemicals released by damaged tissue. Some pain medication works by inhibiting the synthesis of certain chemicals. Sometimes, stimulation of the internal pain receptors is felt as pain from the skin as well as internal organs. This is called referred pain. For example, pain from the heart may be felt in the shoulder.

http://www.sfn.org/skins/main/images/brainbriefings/pain_illus_large.gif

Senses of Taste and Smell

Taste and smell are called chemical senses because their receptors are sensitive to molecules in the food we eat and the air we breathe. Taste cells and olfactory cells bear chemoreceptors. Olfactory cells act from a distance and taste cells act directly.

An adult human has about 3000 taste buds located on the tongue, hard palate, pharynx, and epiglottis. There are 4 primary types of tastes: sweet, salty, sour and bitter, and a 5th, umami may exist. Taste buds open at a taste pore and the taste is interpreted and weighted at the gustatory cortex.

http://www.nature.com/nature/journal/v444/n7117/images/nature05401-f1.2.jpg

Approximately 80-90% of what we perceive as taste is actually due to our sense of smell. Our sense of smell depends on between 10 and 20 million olfactory cells located within the olfactory epithelium. Olfactory cells are modified neurons. An odor's signature is determined by which neurons are stimulated. The neurons communicate this information to the cerebral cortex. The olfactory bulbs have direct connections to the limbic system, which accounts for the aroma-memory connection.

http://www.scienceclarified.com/images/uesc_09_img0525.jpg

Sense of Vision

Vision requires the work of the eye and the brain. The eyeball has 3 layers: the sclera, the choroid, and the retina.

http://library.thinkquest.org/J002508/images/eyeball.gif

The outer layer, sclera, is white and fibrous except for the cornea, which is made of transparent collagen fibers. The middle, thin, darly pigmented layer, the choroid, is vascular and absorbs stray light rays that photoreceptors have not absorbed. The iris regulates the size of the pupil, a hole in the iris center where light enters. The ciliary body contains the ciliary muscle, which controls the shape of the lens for near and far vision. The lens is attached to the ciliary body. The third layer, the retina, is filled with a clear, gelatinous material called the vitreous humor. The retina has a special area called the fovea centralis where cone cells are densely packed. The cornea, assisted by the lens and the humors focuses images on the retina.

http://www.lebct.org/donoreye.jpg (cornea)

The photoreceptors are called rods and cone cells. The visual pigment in rods is a deep purple pigment called rhodopsin. Rods are best suited to night vision because they are very sensitive to light. They also provide peripheral vision and perception of motion. The cones are activated by bright light. Color vision depends on 3 different types of cones which contain different pigments. The optic nerve carries nerve impulses to the optic chiasma. Fibers from the chiasma make up the right and left optic tracts, which take nerve impulses to the visual cortex.

http://www.eyedesignbook.com/ch3/fig3-61retinarods-conesBIG.jpg

Sense of Hearing

The ear has 2 functions: hearing and balance. The sensory receptors are located in the inner ear. The ear itself has 3 divisions: outer, middle, and inner. The outer ear consists of the pinna and auditory canal. The middle ear begins at the tympanic membrane and ends at a bony wall containing 2 small openings; the oval and round window. The bones in the ear are the malleus, the incus, and the stapes. The eustachian tube extends from them iddle ear to the nasopharynx and permits equalization of air pressure. The inner ear has 3 areas: the semicircular canals and the vestibule (equilibrium) and the cochlea (balance).

http://www.hearingprofessionals.co.nz/Images/The-Human-Ear.gif

Sound waves enter the auditory canal and strike the tympanic membrane. THe malleus takes the pressure from the inner surface of the tympanic membrane and passes it, by means of the incus, to the stapes in such a way that the pressure is multiplied about 20x as it moves. The pressure is passed to the fluid within the cochlea. The spiral organ in the cochleas is sensitive to different wave frequencies. The nerve impulses are passed from the cochlear nerve to the auditory cortex.

Sense of Equilibrium

The vestibular nerve arises in the semicircular canals, saccule, and utricle. It takes nerve impulses to the brain stem and cerebellum. Mechanoreceptors in the semicircular canals detect rotational and/or angular movement of the head (rotational equilibrium). Mechanoreceptors in the utricle and saccule detect movement of the head in the vertical or horizontal planes (gravitational equilibrium).

http://cache.eb.com/eb/image?id=14297&rendTypeId=4

References:

Brain (2008)
http://www.med.harvard.edu/AANLIB/home.html

Drugs (2008)
www.drugs.com

Mader, S. (2008) Nervous System and Senses. Human Biology 10th Ed. (p 247-94)

Nervous System (2008)
www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookNERV.html

A Day of Food

2008-04-09T08:23:00.000-07:00

I had a bit of difficulty with this lab as most of the food I actually eat is not listed or is not in the proper fat/carbs/protein ratio that I normally consume.

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

My diet overall is pretty healthy. I am still overweight (again thanks to the evils of prednisone), but my blood pressure and pulse are good (110/68 and 72 bpm.) I have recently quit drinking soda and started drinking a lot more water again. I have an autoimmune disease similar to lupus and I find that the healthier I eat, the better I feel.

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

I probably need to consume a few more calories and lower my fat intake somewhat. My normal fat intake is less than 20 grams per day. The diet does not reflect hydration which is very important. Sometimes thirst is mistaken for hunger. I probably did not drink enough water that day.

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

I find tracking helpful at times but it can lead to the point of obsessing over every little thing you consume. When I was very heavy, I tried a lot of different eating styles and found counting fat grams the most helpful.

Blood Pressure Lab

2008-04-09T08:07:00.000-07:00

High blood pressure (hypertension) is a serious condition that can lead to coronary heart disease, heart failure, stroke, kidney failure, and other health problems.

Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. If this pressure rises and stays high over time, it can damage the body in many ways.

For this lab assignment, blood pressure readings were analyzed for both males and females broken down into the following age ranges: 11-17, 18-24, 25-34, and 45-54. The following table and graph represent the numerical data from the analysis. I could not get a full picture of the table showing the age ranges, but the are reflected along the y axis in the above listed descending order:

The graph represents the table data for the age ranges and gender. The orange line represents female diastolic as the orange key is not visible in the picture. The y axis represents the systolic and diastolic readings and the x axis represents the age ranges.

Journal information:

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

As age increases in both males and females, blood pressure increases. However, the increase in males in more substantial compared to females.

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.

The average blood pressure would increase in both the female and male groups if the age of the subjects increased. If the males were added to the female group respective to age, the average blood pressure for the female group would increase. The reverse would occur if females were added to male groups. Additionally, blending age groups per gender would fluctuate the blood pressure depending upon the age group added and amount of people.

How will you use the investigation screen to test your hypothesis? What steps will you follow? What data will you record?
I recorded the blood pressure data into the table and utilized and compared the information per gender and age group to test my hypothesis.

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

Blood pressure does increase with age for the male group. An anomaly in the female group is a lower blood pressure in the 18-24 range compared to the 11-17 range. Additionally, medical history and informati0on provided explain some of the different and higher results for outside the normal range readings.

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 of the experiment supported my hypothesis for the most part. There is a disparity in the female age groups of 11-17 and 18-24 where the 18-24 is lower. Overall, as age increases, regardless of gender, blood pressure increases.

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?

Outside the normal range blood pressures were evident in both genders starting in the 25-34 groups, although males had a higher instance of that per group. Factors that affected the blood pressure for both groups were: family history of hypertension, high salt intake, lack of exercise, and alcohol consumption.

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

Factors that affected the blood pressure for both groups were: family history of hypertension, salt intake, lack of exercise, and alcohol consumption. Lack of exercise, high salt intake, and alcohol consumption were more prevalent than family history. However, combinations of the 4 resulted in higher readings overall.

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 is a factor in hypertension but obesity alone does not guarantee hypertension. However, an obese person may have other factors (such as the lack of exercise and poor eating habits) that assist in the hypertension.

Food-Healthy or Not?

2008-03-29T02:06:00.001-07:00

Having had a weight problem on and off for most of my life, I look at food as both an enemy and a friend. I have a love-hate relationship with food, and realize the impact is has on me, not only physically, but mentally. Food can get to the point of running (or ruining) your life...can you go to the Christmas party or your friend's house and have dinner? Will there be healthy food? If not, will everyone think you are snotty for not eating? Will they snicker, will they laugh?

The American diet for the most part is pathetic. Processed food, chemicals, irradiation, vitamins, pills, supplements, organic, or not...the list never ends. And that is just the beginning. Part of the problem with healthy eating is it costs more than cheap, processed food. Organic strawberries-$6.00, 8 processed hot dogs-$0.79, healthy food at a decent cost-priceless. Americans are bigger, unhealthier, and seemingly lazier than ever before.

I used to weigh 240 pounds and worked very hard to lose it. I tried many diets, fasts, pills, counting calories, counting fat, counting every ounce of food that entered my body. I became obsessed. I worked at a forklift factory doing security in a plant that had 3 forklift scales that I would weigh on every hour and average my weight. Every hour, eight hours a day, forty hours a week. Could I leave work thinner than when I got there? How much water could I drink to make that happen? What if I ate just fruit or negative calorie food? How many miles could I walk in an eight hour shift? One, two, four, ten?

The only thing that has ever really worked for me is counting fat grams. Nothing else. Eating a diet that did not have a lot of meat, a lot of veggies and fruit, and drinking a lot of water seemed to be the way to go. I would eat around 17 grams of fat a day, but sometimes consume 1500-1800 calories and the weight fell off.

After a few years though I became very ill with an autoimmune disease similar to lupus. At first the doctors thought I was allergic to something I was eating. Start with the basics-red dye, shellfish, nuts, dairy, strawberries, tomatoes, gluten, who knows? I lived on lamb and rice for six weeks trying to isolate the problem. I started to think everything I ate, everything that I absorbed through my skin was causing me to be sick. I was sick for almost four years before anyone had a clue what was wrong.

I once went to a naturopath/chiropractor who told me I needed to eat for my blood type, O-. My blood type begged for meat, especially red meat, and lots of it. I never was a huge fan of meat, but I figured what the heck, I'll try anything. Up until that point I had eaten mostly lacto-ovatarian and felt fine. Eating for my blood type removed my gall bladder, with a doctor's assistance. After I started eating so much meat, I felt awful. How anyone can do the Atkins diet is beyond me.

Overall, I believe a healthy diet consists of a lot of fresh vegetables and fresh fruit, not a great deal of meat (I don't know the last time someone in the US died from a protein deficiency), whole grains, and water-about a gallon a day. Not that I don't like Pepsi and pizza as much as the next person, but I do know what I feel better and healthier eating.

Human Biology

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Three Months

Four Months

Five Months

Six Months

Seven Months

Eight Months

Nine Months

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A Day of Food

Blood Pressure Lab

Food-Healthy or Not?