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Discussion of various anatomy & physiology topics

1. When we become dehydrated, we usually feel thirsty, which causes us to drink fluids. Decide whether the thirst sensation is part of a negative or positive feedback control system and defend your choice?

2, Jimmy, a 12 year old boy was awakened suddenly by a loud crash. He sat up in bed, straining to listen, his fright was revealed by his rapid breathing (hyperventilation) a breathing pattern effective in ridding the blood of CO2. At this point, was his blood ph rising or falling?

3.Dynein is missing from the cilia and flagella of individuals with a specific inherited disorder. These individuals have severe respiratory problems and if males are sterile. What is the structural connection between these two symptoms?

4.Dean, 40 year old aging beach boy, is complaining to you that although his suntan made him popular when he was young, now his face is all wrinkled and he has several darkly pigmented moles that are growing rapidly and are as big as large coins. He shows you the moles and immediately you think "ABCD".What does that mean? Why should Dean be concerned?

5.Why do you think wheelchair-bound people with paralyzed lower limbs have thin, weak bones of the leg and thigh?

6. When a suicide victim was found, the coroner was unable to remove the drug vial clutched in his hand. Explain the reasons for this? If the victim had been discovered three days later, would the coroner have had the same difficulty? Explain.

7. When admitted to the emergency room, John was holding his right hand, which had a deep puncture hole in its palm. He explained he had fallen on a nail while expolaring a barn, John was given an antitentnus shot to prevent neural complications. Tetanus bacteria fester in deep, dark wounds, but how do they travel in neural tissue?

8.Rochelle developed multiple sclerosis when she was 27. After eight years, she lost a good portion of her ability to control her skeletal muscles. Why did this happen?

9.Cynthia a 16 year old girl was rushed to the hospital after takin a bad spill off the parallel bars. AAfter a complete neurological workup her family was told that she would be permanently paralyzed from the waist down. The neurologist then outlined for Cynthia' parents the importance of preventing complications in such cases. Common complications include urinary infections, bed sores, and muscular spasms. Using neuroanatomy knowledge, explain the underlaying reasons for urinary infection, bed sores, muscular spasms?

10. Mr. Frank, a former stroke victim who had made a remarkable recovery, suddenly began to have problems reading. He complained of seeing double and also had problems navigating steps. He was unable to move his left eye downward and laterally. What cranial nerve was the site of lesion? Was it the right or left of this nerve?

11.two year old jimmy has a swollen abdomen and is continuously constipated. On examination a mass was felt over the descending colon and the x-rayt sowed the colon to be greatly distended in that region. What do you think is wrong with Jimmy, and how does this relate to the innervation of the colon?

12.Johnny, a five-year-old boy has been growing by leaps and bounds; his height is 100% above normal for his age. He has been complaining of headaches and vision problems. A CT scan reveals a large pituitary tumor. What hormone is being secreted in excess? What condition will Johnny exhibit if corrective measures are not taken; how would this affect his physical appearance? What is the probably cause of his headaches and visual problems?

13. Why would one not expect to continue increasing in height with age?

14.A woman trying to lose weight buys diet pills off the shelf. She takes them as recommended and notes a quick weight loss. What could cause the sudden weight loss? (The label on the diet pills lists a chemical known to be a strong diuretic.)

Solution Preview

#1: a negative feedback mechanism is one in which the end results feedback to an earlier portion of the feedback loop and causes that portion to decrease in response, while a positive feedback mechanism is one in which a later portion of the cycle feeds back and causes that portion to increase in response. Since the amount of water increases in the blood after drinking, the thirst center recognizes this increase and decreases the thirst response accordingly. It therefore is a negative feedback mechanism.

#2: When CO2 is dissolved in water, what forms? (carbonic acid) If CO2 levels are high, then blood pH is acidic; if CO2 levels are low, then blood pH is alkaline. One of the symptoms of acidosis is an increase in respiration rate, mainly to decrease the amount of CO2 dissolved in the blood.

#3: In cells in the body with cilia or flagella (think those cells lining the respiratory tract and sperm), the movement is created through the interaction of dynein (as a motor protein) and usually myosin fibers. This is similar to the actin/myosin protein complex that creates the shortening of the sarcomere in muscle fibers. So if dynein is not present, not movement of the cilia or flagella can take place. In sperm that leads to no motility, and in the respiratory cells, if the cilia can't beat and eject mucus and whatever the mucus caught (dust, bacteria, etc.) then more infections can result.

#4: ABCD is a medical short hand for people to remember when dealing with cancers of the skin and moles: Asymmetry, Border, Color, and Diameter. Any Google search for ...

Solution Summary

In this solution, we discuss various anatomy and physiology topics.