Presentation Transcript

1. Human Biology

   Part 2
2. URINARY (RENAL) SYSTEM This system consists of the KIDNEYS, URETERS, URETHRA, and BLADDER. Not many structures, but very important. Functions: Regulate electrolytes (K, Na, etc) in body Regulate pH in blood Regulate blood pressure Regulate blood volume Removing metabolic wastes (chemicals produces by chemical reactions in the body are excreted). This is the least important of the kidney’s functions. You can survive for a few weeks without excreting waste products in the urine, but hour by hour, the other functions are more important. LOCATION OF THE KIDNEYS They are toward the back side of the body, partly protected by the lower border of the ribcage.
3. UREA Urea is a waste product of amino acid metabolism. Remember, proteins are made of amino acids, so when you break down proteins, you break down amino acids, and the waste product left over is urea. This is the main waste product in urine. Diuretics are substances that make you excrete more urine. Alcohol, regular coffee, and regular Coca-cola are diuretics. COLOR OF URINE When you urinate, it should be mostly clear with almost no yellow color. The more yellow the urine is, the more dehydrated you are. If the urine is very dark yellow, you are burning too much protein (as in food deprivation).
4. PROBLEMS WITH THE URINARY TRACT UTI (urinary tract infection) needs to be treated, or infection can reach the kidney. UTI can be prevented by drinking lots of water, blueberry or cranberry juice URETHRITIS = infection of the urethra CYSTITIS = infection of the urinary bladder
5. KIDNEY PROBLEMS Things can happen to the kidney: infection, excess proteins, pH change, blood pressure drops, and can lead to kidney failure. Treatment is DIALYSIS, which removes blood, sends it through a filter, and returns it without the wastes. Done three times a week. Ideally, need a kidney transplant because the kidney has other functions as well. The brain, heart, and kidney are the only three organs in the body that have to get oxygen to sustain life.
6. KIDNEY STONES These develop for unknown reasons. Stones are made out of a variety of things: uric acid, calcium, etc. They keep growing. Kidney Stones cause blockage of the urethra, causing the kidney to enlarge. As the kidney stretches, it causes excruciating pain in cycles of hours. As pressure builds up around the stone, urine can pass, and the kidney stone moves down the urethra slowly. Symptomatic kidney stones are pea sized or larger (up to 1 ½ inches). Treatment is ULTRASOUND: Put a powerful speaker on the outside of the kidney, sends a shock wave which the tissues absorb, but the stones shatter so the pieces can pass easier. To help prevent kidney stones, drink enough fluid so your urine stays clear and light colored.
7. NERVOUS SYSTEM Parts of the Nervous System Central Nervous System (CNS): brain and spinal cord. Peripheral Nervous System (PNS): nerves of the body Before we talk about these parts, let’s talk about the nerve cells. The brain has about a trillion nerve cells.
8. NEURONS All neurons do three things: Receive a signal. Transmit a signal to another location. Stimulate another cell Another neuron  transmit signal Muscle  contraction Gland  secretion There are hundreds of different types of neurons, each one is specialized for a particular task (e.g. sense light, smell, tell muscles to contract, etc). They all share certain characteristics.
9. MYELIN MYELIN SHEATH is a coating of lipids around certain types of neurons. It is like the plastic coating around wires we use around the house. It functions to transmit the signals faster. This is important because in a fetus, the only fat in the body is on the myelin sheaths of neurons. Therefore, excess vitamins A, D, E, and K will tend to lodge there and interfere with nerve transmission. MULTIPLE SCLEROSISis an autoimmune disease where the sheaths of the neurons are destroyed, interfering with the neuron functions in the CNS and brain. Starts to manifest in late teens and early 20’s. It progresses to paralysis and sometimes death. There are treatments, but no cure.
10. Nerve Regeneration In humans, axons outside the brain and spinal cord can regenerate, but not those inside. After injury, axons in the human central nervous system degenerate, resulting in permanent loss of nervous function. This is not so in cold water fish and amphibians, where axon regeneration in the central nervous system does occur. So far, investigators have identified several proteins that seem to be necessary to axon regeneration in these central nervous system of these animals, but it may be a long time before biochemistry can offer a way to bring about axon regeneration in the human central nervous system. It is possible though, that one day these proteins will become drugs or that gene therapy might be used to cause humans to produce the same proteins when such injuries occur.
11. Nerve Regeneration In the meantime, some accident victims are trying other ways to bring about a cure. In 1995, Christopher Reeve, best known for his acting role as Superman, was thrown headfirst from his horse, crushing the spinal cord just below the neck’s top two vertebrae. Immediately, his brain lost almost all communication with the portion of his body below the site of damage and he could not move his arms and lags. Many years later, Reeve could move his left index finger slightly and could take tiny steps while being held up right in a pool. He had sensation throughout his body and could feel his wife's touch.
12. Nerve Regeneration Reeves improvement was not the result of cutting edge drugs or gene therapy-- it was due to exercise. Read the exercised as much as five hours per day, especially using a recombinant bike outfitted with electrodes that made his leg muscles contract and relax. The bike cost him $16,000. It could cost less if commonly used by spinal cord injury patients in their own homes. Reeves, who was an activist for the disabled, was pleased that insurance would pay for the bike about 50% of the time.
13. Nerve Regeneration It's possible that Reeves advances were the result of improved strength in bone density, which led to stronger nerve signals. Normally, nerve cells are constantly signaling one another, but after a spinal cord injury, this signal ceases. Perhaps Reeves’ intensive exercise brought back some of the normal communication between nerves. His physician is convinced that his axons were regenerating. Reef was convinced that stem cell therapy would one day allow him to be off his ventilator and functioning normally; however, Reeve died in 2004. So far, researchers have shown that both embryonic stem cells in bone marrow stem cells can differentiate into neurons in the laboratory. Bone marrow stem cells apparently can also become neurons when injected into the body.
14. CENTRAL NERVOUS SYSTEM 1. CENTRAL NERVOUS SYSTEM: The brain and spinal cord THE BRAIN : ANATOMICAL REGIONS  
15. BRAIN The brain is divided into parts. The largest portion is the CEREBRUM, which makes up 80% of the brain. It’s responsible for consciousness and all the complex behaviors, sensations, etc. The cerebrum is divided into 2 halves called CEREBRAL HEMISPHERES. In general, the left side controls the right half of the body, and the right side of the brain controls the left half of the body. These two halves of the brain communicate with each other. Since the brain is so important, it is protected by the skull, cerebrospinal fluid which cushions it, and meninges which are membranes that surround the brain and only let certain substances cross through to the brain.
16. BRAIN The brain is one of the few organs that can only use glucose to get ATP as its energy source. Therefore, without some sugar in our bloodstream, the brain will die. That’s one reason why proper nutrition is so important. By the way, geniuses have the same size brain as everyone else; they are just more efficient at forming synapses. We don’t use 10% of our brains, we use 100%. MENINGES These are tissues that cover the entire CNS. They have fluid between them (CSF) and serve to protect and cushion the brain. HYDROCEPHALUS Hydrocephalus is when the brain swells.
17. CEREBRAL SPINAL FLUID CSF is similar to plasma because it is derived from plasma. Allows the brain to float. The brain has the consistency of Jell-O, and weighs three pounds. Its weight would crush the inferior structures if it didn’t float. It cushions. In sudden movement, like riding a bike into a tree, and hitting the head on the tree, the brain hits inside the skull in the front, and then in recoil it hits the back of the skull = closed head injury, not necessarily with a fracture.
18. MENINGITIS Meningitis is an infection requiring a spinal tap for diagnosis. This is when the meninges become infected. Can be caused from virus (not that bad) or bacteria (can be fatal). The main symptom is a headache, so when this occurs in an infant, they can’t say where they hurt. So when an infant presents with a high fever of 104˚ with no other symptoms, they will usually test for meningitis, because if they miss it, it’s fatal. The test is a SPINAL TAP, where a needle is inserted in the low back below the level of the spinal cord. They draw the CSF to look at. It it’s cloudy or bloody, it’s usually meningitis.
19. HIGHER FUNCTIONS OF THE BRAIN(control behavior and emotion) BEHAVIOR THE FRONTAL LOBE involved in planning and judgment. How much time do you need to be ready for the test? Damage here causes people to become docile and do what they are told. 1930’s when people acted up, they did a pre-frontal lobotomy by going up the eyelid and stirring up the brain. Stopped in 1960’s; we do it with drugs now. There was a 16 year old rebel who shot himself in the head, but the bullet went too far forward, and his personality improved! Riddlin suppresses CNS in children, stimulates it in adults. In a criminal psych ward, an inmate with a lobotomy got his hand caught in the electric door, and while his hand was dangling half off, a nurse asked him if it hurt, and he just calmly said, “Yes, quite a lot.” No emotion. Remember, when you kill a neuron, it does not regenerate; it’s gone forever.
20. MEMORY You have different types of memories MOTOR MEMORY is when you remember things by using your body movements. Drummers and people who play other percussion instruments are good at this. When someone asks you to spell a word and you have to say, “Wait a minute” and you have to write it out, that’s because you learned the word with motor memory. MEMORY OF EVENTS is when you remember people and events. This type of memory is also used to convert short term memory into long term memory. When you have to look up a phone number, and then forget it 5 minutes later, that’s short term memory. Memorizing new material is accomplished in two ways: Repetition Context You can’t learn anything brand new; you have to add to what you already know, by putting it into context.
21. AMNESIA AMNESIA is not caused by a blow to the head; it has to be damage deeper, like from a stroke. Also, a second blow doesn’t cure the first one! Strokes and Alzheimer’s are most likely to cause amnesia.Nemo’s fish friend, Dorothy, has RETROGRADE AMNESIA, which is when a person cannot remember anything new at all. You can get around amnesia by using motor memory. Give an amnesiac a new puzzle; they’ll do it in 30 mins. The next day, they don’t recognize the puzzle, but they do it in 20 mins, the next day in 10. Therefore, they are learning by motor memory. They can learn their route from home to the market by repetition. But they can’t make a detour, and if anything bumps them off track, they’ll be lost.
22. MEMORY No one can remember new things, so you need some context; you need to associate the new thing with something you are already familiar with. That’s why pneumonics are good. If the word “cerebrum” is a brand new word, it sounds like “Sir read broom”, which are words you already know and can visualize. Think of Harry Potter asking a wizard to read the strange words on his new broom: “Sir read broom”, and the wizard scratches his brain (cerebrum) as he tries to read the words. Now it’s easy to remember because you can relate it to something you already know and can picture.
23. FUN FACTS Bees tell other members of the hive where food is by doing a special dance that relays distance and direction. Octopus have the ability to sort out complex problems on their own A dolphin doesn’t need to see to catch a meal. It sends out sound waves which bounce back and create a 3D ultrasound picture of it, even in complete darkness. A dolphin’s brain in relation to its body is larger than that of a chimpanzee or great ape. Dolphins are one of the most intelligent mammals; they've learned to sleep using only half their brains. While one half rests, the other remains alert and continues the respiratory process, without interruptions. The brain of a roach is located in its body, and if by accident (natural or human) it should lose its head, it can live up to nine days completely decapitated. It dies from starvation.
24. SPINAL CORD Really, this is just a continuation of the brain. The primary functions of the spinal cord are for simple reflexes and to be a link between brain and body If a person has a spinal cord injury in their cervical region, they could have quadriplegia (arms and legs paralyzed). If a person has a spinal cord injury in their thoracic region, they could have paraplegia (legs only)
25. THE EYE What did the right eye say to the left eye?Between you and me, something smells! GLANDS OF THE EYE 1. LACRIMAL GLANDS are the largest set. They are on the superior lateral eyelid (overhead) and they produce tears, which have enzymes to kill bacteria (which thrive in warm, moist conditions). The tears moisten and lubricate the eye surface. They drain out into the LACRIMAL DUCT, which is seen as a small hole in your lower inner eyelid. 2. LACRIMAL CARUNCLE(“little meat”) is the spot on the medial corner of the eye. It makes an oily secretion to lubricate the eye for the eyelids. When the secretion dries, it is called “sand” in the eyes. 3. CILLIARY GLANDS go to only the cilia. When clogged = STY.
26. PROBLEMS WITH THE LENS PRESBYOPIA: (“old eyes”). Occurs around age 45-50. With age, the lens loses flexibility. It stays in the position for seeing far, so there is trouble focusing on things that are near. CATARACTS: Clouds in the lens which can completely cloud the eye. Treatment is to remove the lens and replace it with a plastic one.
27. VISION PROBLEMS HYPEROPIA (far-sighted) eyes are too short; can’t see up close MYOPIA (nearsighted) eyes are too long; can’t see far away. Normal eyes are perfect spheres. Myopic eyes are elongated (overhead projector is in focus, but move it backward, gets fuzzy. Even badly nearsighted eyes are only 1mm from normal. Treatments are glasses or Lasix, which is laser surgery on cornea, when it’s shaved so it focuses light farther back to reach the retina. Contact lenses were invented by Leonardo da Vinci in 1508.
28. VISION PROBLEMS ASTIGMATISM Cornea has an irregular shape. Part of the field of view is out of focus. They eyeball changes shape until age 24. RETINAL DETACHMENT The retina separates from the underlying blood supply. Looses oxygen, cells die. Usually caused by an injury like a baseball, punch, or airbag to the eye. Treatment is lasering to spot-weld it back. Manifests as a shimmering light. Needs immediate treatment. Those who are most vulnerable are those who are nearsighted.
29. VISION PROBLEMS MACULAR DEGENERATION The size of the macula is the size of the printed letter “O” in 14 pt font. When the macula degenerates, you lose a lot of sight. This is the most common cause of blindness in the US. It’s due to bleeding in the eye, causing scar tissue. The retina does not get enough oxygen, and the cells die. Macular degeneration allows vision in the periphery, but they can’t read or drive. DIABETIC RETINOPATHY This is when the high sugar levels destroy the photoreceptors in the retina. The blood vessels also swell and rupture and the clots block vision. Some of this damage can be repaired by using a laser to evaporate the blood clots, but any damage to the photoreceptors is permanent. It can lead to blindness.
30. VISION PROBLEMS If a child is blind until age 4-5, and then you restore the sight, he will still be blind because the brain doesn’t form properly. With kids who have astigmatism or weak eye muscles, one eye stops seeing (or sees double). The thalamus in the brain will shut off all the signals from the bad eye. GLAUCOMAToo much aqueous humor  pressure on the anterior chamber and retina  blindness. This form of blindness is more common in third-world countries because we have tests to detect it and treat it. The test measures how much pressure there is here by seeing how easily the cornea is deformed, either with air or direct pressure. How many of you have had this test?
31. THE EAR The sensory functions of the ear include not only hearing, but balance, too. 1. OUTER EAR A. EXTERNAL AUDITORY CANAL. B. PINNA: The cartilage around your ear. The pinna funnels sound in. If you cup your hands to your ears (do it now), you’ll notice the sound of my voice is louder.
32. MIDDLE EAR 2. MIDDLE EAR is an air filled space (overhead) with structures. A. TYMPANIC MEMBRANE (ear drum) vibrates in response to sound. Attached to it are 3 bones called OSSICLES which are the smallest bones in the body 1) MALLEUS (hammer) 2) INCUS (anvil) 3) STAPES (stirrup). Together, these three bones are only one inch long. Their function is to transmit sound vibrations. The malleus vibrates the incus, which vibrates the stapes. B. AUDITORY TUBE connects the middle ear to the nasopharynx, and is only the thickness of a pencil lead. If this tube is closed, the ears feel plugged up. Its function is to equalize the pressure of the middle ear and the outside air to allow the bones to vibrate freely. Tubes are put in the tympanic membrane to drain fluids in kids.
33. INNER EAR 3. INNER EAR isa complex structure. The main structure of the inner ear is the COCHLEA (“snail shell”). When the stapes vibrates, it causes the fluid in the cochlea to vibrate, which triggers HAIR CELLS which are mechanoreceptors that sense vibrations and send the information to the brain. This portion of the inner ear is responsible for hearing. SEMI-CIRCULAR CANALS are the portion of the inner ear that is responsible for balance. There are three of them, and they determine movement in three planes. Within each canal is fluid and hair cells (mechanoreceptors), which connect to nerves that go to the brain. When you move in one direction, like sliding across the room, the fluid sloshes like a cup of coffee, and it makes the hair cells move. Within the endolymph here are
34. EAR PROBLEMS OTOLITHS (“ear rocks”) which are calcium deposits. When you stand perfectly upright, these otoliths fall directly down and bend the hairs on the lower cells. When you tip your head to the side, they will stimulate the hairs on the opposite side. These stimulate the nerves to tell you what position your head is in. Therefore, the sense of balance uses mechanoreceptors. VERTIGO (dizziness): Inflammation of the semi-circular canals gives you a sense of motion when you’re not moving.This can be debilitating. Sometimes only one canal is affected, so you only get dizzy if you turn your head one way.
35. Hearing Loss It is easy to take the sense of hearing for granted. But in fact many people eventually lose some or all of their ability of hear. There are two broad categories of hearing loss: conduction deafness and nerve deafness. In conduction deafness, sound waves are not conducted to the cochlea by the usual pathway: through the auditory canal to the tympanic membrane, then via the the oval window to the fluid filled cochlea. Instead, sound waves must travel through the bones of the skull. In nerve deafness, sound waves should be transmitted to the cochlea, but there is a problem with the nervous structures associated with the hearing, such as the hair cells of the spiral organ, the cochlear nerve, or even in the auditory portions of the cerebral cortex.
36. Hearing Loss There are numerous causes of conduction deafness. Anything that affects the ability of the tympanic membrane to vibrate may result in hearing loss. For example, ear wax can build up in the auditory canal, and press on the membrane. Inserting objects into the ear can damage the tympanic membrane. Some people develop conduction deafness as they get older. This may result from arthritis in which the bones of the middle year to use. The good news is that this type of disorder is often correctable with surgery.
37. Hearing Loss Otitis media is an infection of the middle ear that can lead to conduction deafness. It typically occurs when an upper respiratory infection, such as a cold, leads to swelling of the auditory two, creating a vacuum that pulls fluid into the middle ear. The fluid provides an ideal environment for bacteria or viruses, and the pressure it exerts causes symptoms such as pain, ringing in the ears, and hearing loss. The loss is usually incomplete, and rarely permanent. However, when such hearing loss occurs in very young children, it can delay their speech development. If the tympanic membrane ruptures under pressure, it usually heals on its own in a matter of weeks. If it does not rupture, fluid may linger in the middle ear, and in some cases a tube must be surgically inserted for drainage.
38. Hearing Loss Noise exposure is a common and usually preventable cause of nerve deafness. Noise volume is measured in units called decibels. Any noise above a level of 80 dB could result in damage to the hair cells of the year. Eventually, the hair cells disappear completely. If listening to city traffic for extended periods can damage hearing, it stands to reason that frequent attendance at rock concerts, constantly playing a stereo loudly, or using earphones at high volume is also damaging to hearing. The first-hand of danger could be temporary hearing loss, a feeling of fullness in the ears, muffled hearing, or ringing in the ears. If you have any of these symptoms, modify your listening habits immediately to prevent further damage. If exposure to noise is unavoidable, specially designed noise reduction earmuffs are available, and it is also possible to purchase earplugs made from a compressible, spongelike material at the drugstore or sporting goods store. These earplugs are not the same as those worn for swimming, and they should not be used interchangeably.
39. Hearing Loss Aside from loud music, noisy indoor or outdoor equipment, such as a rug cleaning machine or a chainsaw, is also troublesome. Even motorcycles and recreational vehicles such as snowmobiles can contribute to gradual loss of hearing. Exposure to intense sounds of short duration, such as a burst of gunfire, can result in an immediate hearing loss. Hunters may have a significant hearing reduction in the ear opposite of the shoulder where the gun is Kerry. The butt of the rifle offers some protection to the year nearest the gun when it is shot.
40. Hearing Loss Certain over-the-counter and prescription drugs have the potential to cause nerve deafness when taken in combination or excessive amounts. Such medications include anti-inflammatory drugs such as aspirin, ibuprofen, Tylenol, antibiotics, anticancer drugs, quinine, and certain blood pressure medications. Sometimes hearing is restored when a person stops taking the medication, but in other cases the damage is permanent.
41. Hearing Loss One uncommon cause of deafness is autoimmune inner ear disease. This occurs when a person's immune system turns against normal, healthy tissue. The person experiences symptoms such as dizziness and ringing in the ears in addition to hearing loss. Although it can be treated with drugs that suppress the immune system, the drugs themselves can have serious side effects, and may only slow the disease.
42. Hearing Loss Hearing aids can help with partial hearing loss such as that caused by chronic noise exposure, but they do so by amplifying sound waves rather than restoring lost earring. Most amplify all sound waves equally, which is why it may be difficult for someone wearing a hearing aid to carry on a conversation in a noisy restaurant. Some of the newer and more expensive hearing aids are programmable, so the level of amplification can be adjusted depending on the noise level of one's surroundings. Through the use of cochlear implants, there is hope today for people who have little or no hearing due to cochlear damage. A person with a cochlear implant wears a microphone picks up sounds and sends them to a processor, which relays signals to a small receiver implanted beneath the scalp. The receiver transmits signals through a number of electrodes to the origin of the cochlear nerve. Cochlear implants are not yet capable of producing all of these sounds of normal hearing, but they do allow people who have them to understand speech and perceive sounds such as alarms and telephones.
43. Hearing Loss Nova Hearing Aid: http://video.yahoo.com/video/play?vid=1074768518&fr=yfp-t-471 Sudden Hearing Loss: http://texasent.com/newtexasent/media/video/video_files/Sudden_hearing_loss_2002_360X240.swf Deaf Baby with Hearing Aid: http://video.yahoo.com/video/play?vid=421542&fr=yfp-t-471
44. ENDOCRINE SYSTEM The endocrine system is all the organs of the body that are endocrine glands. An endocrine gland secretes hormones. Hormones are substances that are secreted by one group of cells, enter into the bloodstream, and travel to another group of cells (organs) and have an affect there. Hormones regulate growth, reproduction, chemical balance, and metabolism. The endocrine system is controlled directly by the pituitary gland. The pituitary gland is controlled by the hypothalamus in the brain.
45. 1. HYPOTHALAMUS This is located at the base of the brain (overhead). It secretes hormones that affect the pituitary gland. 2. PITUITARY GLAND produces many important hormones, including: A. THYROID STIMULATING HORMONE (for metabolism rate) B. GROWTH HORMONE: Overproduction results in giantism C. URINE OUTPUT D. CHILDBIRTH CONTRACTIONS
46. THYROID GLAND 3. THYROID GLAND located inferior to Adam’s apple; makes THYROID HORMONE. Thyroid hormone contains iodine. If a person doesn’t eat enough iodine, they can’t make thyroid hormone. The hypothalamus and pituitary gland will release more hormones to stimulate the thyroid gland, but the thyroid can’t respond, so it grows GOITER. This is usually caused by too little iodine in diet. That’s why salt is iodized. Iodine is only found in seafood, so if salt wasn’t iodized, a lot of people wouldn’t get enough iodine, and there would be a lot of goiters. There are more problems with the thyroid gland than any other organ.
47. PARATHYROID GLANDS 4. PARATHYROID GLANDS are 4 little glandsembedded in the thyroid gland. They make PARATHYROID HORMONE  controls calcium levels.
48. PANCREAS The pancreas makes many substances, including digestive enzymes, insulin, andhormones. INSULIN controls blood sugar levels. It takes sugar out of the bloodstream and brings it into the cells. If there is not enough insulin, the blood sugar level rises and can lead to coma and death. This condition is called DIABETES.
49. ADRENAL GLANDS 6. ADRENAL GLANDS (“On top of the kidney”) They are increased during all times of stress. A. CORTISONE  reduces inflammation B. ESTROGEN sex hormone produced by males and females. C. TESTOSTERONE produced by males and females. The circus lady with a beard most likely has a malfunctioning adrenal gland. D. ADRENALIN (epinephrine). When you are spooked, the neurons fire.
50. DANGERS OF STEROIDS Steroids that weightlifters take are synthetic testosterone, and they are taken in doses 100x larger than a prescription, so they are dangerous. Although they increase muscle size, they decrease the size of testicles and cause a low sperm count, impotence, and sterility. They increase rage and aggression as well. Other side effects are that they cause baldness, give women hair on their face and chest, enlarge the breast of males and decrease the breast in females, cause kidney and liver disease, cancer, severe acne, high blood pressure and high cholesterol, can stunt growth in those whose bones have not finished growing yet, and they can shorten the life span by several decades.
51. Melatonin Melatonin is one of the least understood hormones; it does not cause dramatic changes in the body like many of the other hormones. It is produced by the pineal gland of the brain and is often referred to as the hormone of darkness because it is secreted only at night and it is inhibited by light. Some people refer to it as the werewolf hormone. It was this unique pattern of secretion that provided clues to one of its major functions: it supplies time of day information to the body. Most of our cells are unable to assess the time of day and they depend on a special center in the brain to keep time.
52. Melatonin One of the clearest effects of melatonin is the ability to reset the body's internal clock for blind people or those suffering from jet lag or in night shift workers. Melatonin administered in the afternoon shifts the sleep cycle so that people wake up and go to sleep earlier. Melatonin given in the morning causes people to wake up and go to sleep later. This capability of melatonin to shift the body's internal clock will likely find increasing use in the future as travel for business and pleasure become more international. It should also be especially useful in sports where teams playing in international competitions now have to override a week before an event in order for there internal rhythms to shift naturally so they can play at their best.
53. Melatonin Another timekeeping function of melatonin is its role in orchestrating seasonal changes. For example, it plays a major part in signaling the body of animals to hibernate. In this capacity, it is believed that melatonin is instrumental in causing tissues to shift into a state of metabolic inactivity during hibernation. This capability has led some researchers to propose that melatonin might be able to induce a hibernation-like state and donor organs prior to transplantation in order to prolong their shelf life.
54. Melatonin In seasonally reproducing animals, melatonin plays a part in directing the reproductive system to become inactive. Because of this ability to regulate seasonal activities, there has been interest in the role that melatonin might play in seasonal affective disorder (SAD), which makes some people depressed in the winter. The present evidence indicates that the short days of winter cause excess melatonin to be produced in individuals susceptible to this disorder. It appears that in people with SAD, the melatonin system does not respond to artificial lighting, while in unaffected people the system ceases production of melatonin in response to artificial lighting. Interestingly, in many people with SAD, special bright lights that mimic sunlight are effective in shutting down the melatonin and alleviating depression.
55. Melatonin Although melatonin is widely advertised as a sleep aid, there is controversy among scientists about what role it plays in sleep it does not appear to work like a sleeping pill that simply induces sleep, rather it seems to produce a physiological bias toward sleep. As people get older, the amount of melatonin they produce at night decreases, while insomnia and other sleep problems increase. Alzheimer's patients have less melatonin than normal. Fortunately, a few studies have already shown that melatonin treatment can cause significant improvements in the sleep quality of both elderly insomniacs and Alzheimer's patients. If melatonin can be used to reestablish more normal sleep patterns in Alzheimer's patients, it should help delay their institutionalization and reduce the psychological, physical, and monetary burden of this devastating disease.
56. MALE REPRODUCTIVE SYSTEM 1. THE AMAZING PENIS This organ can vary in size from 1” to 6” in seconds, while maintaining the integrity of the blood vessels, nerves, and lymphatics. Viagra is a medicine which allows vasodilatation (to encourage a penile erection), but if you have heart disease, it can give you a heart attack. Viagra can also cause vision problems. An erection squeezes the veins shut so the blood can’t leak out. If Viagra (or anything else) causes an erection for longer than four hours, the erection decreases the blood flow, and the tissue is killed.
57. SCROTUM 2. SCROTUM A. TESTICLES makes sperm. B. VAS DEFERENS is the tube that the sperm goes into. C. PROSTATE GLAND is where the vas deferens passes through. D. SEMINAL FLUID is the liquid that carries the sperm. It is made by the prostate gland. E. SEMEN is the seminal fluid plus the sperm. The semen is then dumped into the urethra during ejaculation. The urethra is the same tube that excretes urine. In order for sperm to be produced, the temperature has to be a few degrees lower than normal (35˚C or 94˚F instead of 37˚C or 98˚F). To insure a lower temperature, the testes are located outside of the body, in the scrotum (outside of the pelvis). The temperature is maintained by muscles that elevate and depress the testes.
58. PROBLEMS There is an opening in the groin area called the INGUINAL CANAL. If you do heavy lifting, it increases the abdominal pressure, and intestine gets pushed into it = INGUINAL HERNIA (surgery). To check for hernia, feel scrotum, and cough. Should be a little movement, but the testes should not move all the way up. VASECTOMYis the #1 birth control method in the US. An incision is made in back of the scrotum, cut out a piece of the vas deferens. It is possible to reverse it, but it is assumed permanent. Only 1 in a million grows back together in 5-10 years. Infertility The most frequent cause of infertility in males is low sperm count and/or abnormal sperm. Disease, radiation, chemicals, high testes tempera­ture, and drug abuse can also contribute to this condition.
59. PROSTATE GLAND The urethra goes through the middle of the prostate, which continues to grow throughout life. By the time men are older, most of them have PROSTATIC HYPERTROPHY (enlarged prostate). It can constrict the urethra, making it hard to urinate. Needs surgery to open. Prostate cancer affects 10% of the male population. To check for cancer of the prostate, do a rectal exam. A finger is placed in the rectum and the prostate can be palpated. It should be part of a routine physical. If the prostate needs to be removed, there are nerves that might be severed that run along it, causing erectile dysfunction.
60. FEMALE REPRODUCTIVE SYSTEM Consists of the following: 1. Ovaries 2. Fallopian Tubes 3. Uterus 4. Vagina 5. External genetalia
61. OVARIES These are about one inch around. OVARIAN CYCLE This is the process of egg development on a monthly basis. Eggs develop during fetal development. A woman is born with all the eggs she will ever have; about half a million. At puberty there is a change in hormones which causes development of some of these eggs. The two hormones that influence the development of female secondary sex characteristics are estrogen and progesterone.
62. OVARIAN CYCLE The average ovarian cycle is 28 days. Day 1 This is the first day of menstruation. The new eggs in the ovary begin to develop. Day 14 OVULATION. sperm live for 7-10 days. That means that you can have sex during menstruation, and the sperm might live inside past ovulation. There is no safe time to have unprotected sex. Unprotected sex once a week = 90% chance of pregnancy. When the egg is released, it goes into the fallopian tube.
63. Infertility One of the most common causes of infertility in women is STD (sexually transmitted disease). We’ll talk about that later. Also, Fat is needed to have the menstrual cycle. Skinny and athletic women may not menstruate. Women who have trouble conceiving take fertility pills, which causes 100 eggs to develop, 4-5 of which may mature  multiple births. Therefore, fertility pills frequently result in multiple births. A diaphragm is a cup-like structure that a woman can insert in the vagina to block the sperm from getting in. However, it is not very effective because it requires significant skill. IUD (intra-uterine device) is implanted in the uterus by a doctor and prevents implantation. However, it can cause infection.
64. Birth Control Birth Control Pills are made of estrogen, so they inhibit the development of the eggs, but the uterine lining still grows. You take them for 3 weeks, and then take one week off to allow for menstruation. They are 99% effective if taken properly. You have to be careful to take the pill not only every day, but at the same time every day, to keep from getting pregnant. Some of the new estrogen pills can cause a period only every 3 months instead, but there are side effects: Birth control pills can cause a heart attack Stop BCP 6-12 months before planning conception, or there may be birth defects. Implantable birth control = NORPLANT,etc (capsules of estrogen surgically implanted under the skin of the arm), releases tiny amount of estrogen continually. Condoms are also 99% effective if used correctly; if not, only 85% effective. Solution = put the woman in charge of the condom, and the failure rate drops dramatically. A Condom can rupture by applying hand lotion
65. ECTOPIC PREGNANCIES The egg is normally fertilized in the fallopian tube, goes down into the uterus and implants there. If it implants in the fallopian tube = ECTOPIC PREGNANCY. This is fatal to the mother and embryo, but nowadays there are few deaths of the mother because it is very painful, so she will go to the ER and they will do surgery. A woman who goes into the ER with abdominal pain will always get a pregnancy test.
66. STD Sperm swim out of the opening of the fallopian tube and into the body cavity. That means any STD can also enter there, causing PELVIC INFLAMMATORY DISEASE (PID), where it spreads to all organs in the pelvis. This STD is chronically extremely painful for the rest of the woman’s life, and there is no cure and no treatment. The most common cause of infertility in women is STD. The inflammation and scarring closes off the fallopian tube.
67. TUBAL LIGATION TUBAL LIGATION is a method of birth control where a piece of the fallopian tube is cut out, and there’s no way for the sperm to reach the egg. It is more complicated than a vasectomy, so it is done less often than a vasectomy.
68. UTERUS The uterus consists of a BODY, CERVIX, and VAGINA. The cervix is the neck of the uterus. PROBLEMS WITH THE UTERUS ENDOMETRIOSIS is a very strange condition. Pieces of the uterus wall (endometrium) are supposed to fall down the vagina during menstruation, but sometimes its cells go up the fallopian tube and enter the body cavity. They can lodge anywhere; on top of the lung, kidney, etc. These cells still respond to hormone changes, grow, and break down and die, causing a lot of weird pain during menstruation. It’s difficult to diagnose because the pain goes away before the doctor appointment. The symptoms vary, depending on the location. One lady had it on her lung and got a collapsed lung every month. Treatment is to give hormones to prevent menses.
69. UTERUS PROBLEMS FIBROIDS These are benign tumors like scar tissue. They can get large and be painful, especially during contraction of menses and pregnancy. Fibroids are the most common reason for hysterectomy (surgical removal of the uterus). HYSTERECTOMY comes from the Greek “hysteria”. It was thought that only women get hysterical because they have a uterus. Now we know that’s not true. They get hysterical because they have ovaries! The surgery involves going through the abdominal wall, cut the fallopian tubes, and yank the uterus out through the vagina.
70. FUN FACTS Be glad you’re not an octopus. They die after laying their eggs or after mating. However, if you remove an octopus's reproductive organs, it can live until a ripe old age - albeit bored and without much company. Lions have sex every 15 minutes for an entire week. However, this only occurs every two years. The pig has the longest orgasm; it can last up to 15 minutes.
71. FUN FACTS Every human spent about half an hour as a single cell.A fetus acquires fingerprints at the age of three months. If we could breed like a rabbit, we could produce 6 babies a month! The mammal with the largest number of births is the Tasmanian Devil, which gives birth to about 50 tiny babies at a time. The largest egg layer is the kiwi, whose egg is about 25 percent of it's total weight! That would be like a human having a 30 pound baby. The paradoxical frog tadpole is five times larger than its parents. A giraffe gives birth standing up, so the baby has a 5 foot drop to the ground. This stimulates breathing and helps the placenta to detach.
72. The Theory of Evolution The term theory in science is reserved for those ideas that scientists have found to be all encompassing because they are based on data collected in a number of different fields. Evolution is a scientific theory. So is the cell theory, which says that all organisms are composed themselves, and so is the atomic theory, which says that all matter is composed of atoms. No one argues that schools should teach alternatives to the cell theory or the atomic theory. Yet controversy reigns over the use of the expression “the theory of evolution”.
73. The Theory of Evolution No wonder most scientists in our country are dismayed when state legislatures or school boards rule that teachers must put forward a variety of “theories” on the origin of life, including one that runs contrary to the massive data that supports the theory of evolution. An organization in California called the Institution for Creation Research advocates that students be taught an “intelligent-design theory”, which says that DNA could never have arisen in without involvement of an intelligent agent, and that gaps in the fossil record mean that species arose fully developed with no antecedents.
74. The Theory of Evolution Since our country forbids the mingling of church and state-- that is, no purely religious ideas can be taught in the schools-- the advocates for an intelligent design. Our careful not to mention the Bible or any strictly religious ideas such as “God created the world in seven days”. Still, teachers who have a solid scientific background do not feel comfortable teaching and intelligent design theory because it does not meet the test of a scientific theory. Science is based on hypotheses that have been tested by observation and/or experimentation. A scientific theory has stood the test of time-- that is, no hypothesis that runs contrary to the theory have been supported by observation and/or experimentation. On the contrary, the theory of evolution is supported by data collected in such wide ranging fields as development, anatomy, geology, and biochemistry.
75. The Theory of Evolution Polls consistently show that nearly half of all Americans prefer to believe the Old Testament account of creation. That is their right, but should schools be required to teach and intelligent design?