Q4. Explain why oral contraceptives, which artificially raise levels of estrogens and progesterone, prevent pregnancy.
Q5. Diazepam is a drug that stimulates the activity of GABA receptors in the brain. If a person was having an epileptic seizure, how would diazepam affect the seizure?
Q6. During a surgical procedure, an anesthesiologist administers to the patient an inhaled anesthetic agent that opens Cl- channels in the postsynaptic membranes of neurons of the brain. Explain why this would put the patient “to sleep” for the duration of the surgical procedure.
Q7. Jack places his foot on a piece of broken glass. He immediately lifts his leg away from the glass without losing his balance. What reflex response has occurred? How does he manage to maintain his balance?
Q8. Which cranial nerves would be affected by a drug that stimulates the parasympathetic nervous system? Predict potential adverse effects that one might experience.
Q9. Mr. Putuu has been diagnosed with Horner syndrome, which is caused by dysfunction of the sympathetic neurons in the superior cervical ganglion that innervate structures of the head, face, and neck. What symptoms is Mr. Chevalier likely to face due to his disease? Explain.
Q10. The juxtamedullary nephrons of animals adapted to survive with minimal water consumption, such as desert rats, have relatively much longer loops of Henle than humans have. Of what benefit would these longer loops be?
Q11. Alcoholic beverages inhibit vasopressin secretion. Given this fact, predict the effect of alcohol on the rate of urine formation. Predict the actions of alcohol on ECF osmolarity. Explain why a person still feels thirsty after excessive consumption of alcoholic beverages
Q12. A black market for growth hormone abuse already exists among weight lifters and other athletes. What actions of growth hormone would induce a full-grown athlete to take supplemental doses of this hormone? What are the potential detrimental side effects?
Q13. Ama, a 17-year-old college student, suffers from an eating disorder. Her percentage of body fat has dropped to 14%. Her menstrual cycles were irregular, and now they have stopped altogether. Why do you think this has happened? Could the lack of menstrual periods be beneficial in this situation? Explain.
Q14. A 60-year-old man has been taking an herbal medication for impotence. Recently, he has been having periods of dizziness when he is exercising and has started to check his blood pressure, which drops after he takes the medication. Why do you think a medication that prevents impotence also affects blood pressure?
Q15. You have read that aldosterone causes sodium ion retention from the kidneys. How would blocking aldosterone secretion decrease the amount of water retained from the fluid in the kidneys?
Q16 (a) Mr. M is a patient with type I diabetes mellitus. He presents with dizziness, rapid breathing, confusion, and weakness. You find out that he forgot to inject his normal dose of insulin this morning. Will his blood glucose concentration be normal? Explain. Your colleague suggests that Mr. Montez needs to ingest some sugar. Is this going to help him? Why or why not?
Q16 (b) What has likely happened to the pH of Mr. M’s blood? What does this mean about the hydrogen ion concentration in his blood? How will his buffer systems respond to this change in pH?
Q17. Women with inadequate secretion of GnRH are often treated for their infertility with drugs that mimic the action of this hormone. Can you suggest a possible reason that such treatment is often associated with multiple births?
Q18. A patient has a brain tumor that necessitates removal of his pituitary gland. Will its removal affect production of ADH and oxytocin? Explain.
Q19. A professional male athlete has been taking a synthetic testosterone supplement for several months. He and his wife have been trying to have a baby, with no success, and have decided to begin treatment for infertility. Before testing the man’s sperm count, the doctor discovers that the man’s LH levels are very low. Why do you think his LH levels are low? Would low LH levels affect sperm production?
Q20. A male athlete taking large amounts of an androgenic steroid becomes sterile (unable to produce sperm capable of causing fertilization). Explain.
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