1. Imagine a person with a hypothalamic tumor that produces excess Thyrotropin Releasing Hormone (TRH).
(A) How would this affect this person?
(B) List two normal processes in the endocrine system that might be able to partially compensate for these changes:
(A) Would increase the rate of TSH and prolactin released from the pituitary gland. The increase in TSH would cause excess T3 and T4. Excess TRH inhibits dopamine which releases prolactin which then decreases GnRH. GnRH stimulates the production of FSH and LH. Ultimately, the gonads wouldn’t function and the hormones would not be present. A female would not ovulate and a male would not produce testosterone.
(B)Humoral stimuli: parathyroid involved
Nervous system modulation
2. A patient presents with a mutation in their growth hormone receptor (GH-R) that does not change specificity of the hormone, but greatly increases the affinity of GH-R for growth hormone (GH). How would this affect growth?
GH would remain bound to GH-R much longer causing much greater effects with the same amount of hormone. It would cause increased growth and protein synthesis, and poor control over the growth rate. It would do the same to the GH-R that mediates the negative feedback effects of GH in the hypothalamus, so this effect might be largely compensated via negative feedback. It would be impossible to adjust the rate of growth rapidly by decreasing GH secretion.
3. Imagine a person whose Expiratory Control Neurons in the base of the brain are non-functional. How would this affect breathing in this person?
The person would have to voluntarily expire; it would not automatically occur.
4. During pregnancy, females do not continue to cycle and they do not ovulate. Briefly, explain how hormone(s) of pregnancy block cycling and ovulation.
When the follicle containing the egg bursts, the egg is released and the follicle becomes the corpus luteum. The corpus luteum produces progesterone that not only keeps the egg impanted and growing, but also blocks the release of more hormones such as LH and FSH from the pituitary gland to prevent ovulation from occurring during pregnancy.
5. If a patient is given a drug that blocks Beta adrenergic receptors, what affect, if any, would you predict on cells in the liver?
An adrenergic drug is supposed to mimic the sympathetic nervous system. Beta receptors inhibit glycogenolysis and glucogenesis, and stimulate insulin secretion. Liver cells release glucose to the blood stream during glycogenolysis and glucogenisis. Beta blockers act like an antagonist to beta receptors and block inhibition of glycogenolysis and glucogensis and stop insulin secretion. Hepatocytes would be blocked and glucose would not be freely released.
6. A new diet aid involves cooking foods using fats such as ‘Olestra’ that are not digestible by human lipases. Imagine that these fats CAN bind to fat-receptor proteins in the gut, even though the fats cannot be digested or absorbed. How would these fats affect digestion, and why?
The fats would bind to the receptor but wouldn’t get digested or absorbed. They would just block the receptors from others fats to be digested. The ‘Olestra’ being bound would not give any fats or calories. The ‘Olestra’
would bind to fat receptor proteins but enzymatic activity would not be activated. No fatty acids or triglycerides would be absorbed during digestion.
7. One form of performance enhancement for athletes is blood ‘doping’—removing RBCs, storing them while the body produces more, and then reinjecting the stored RBCs before the athletic competition. (Not legal for most sports) This loads the circulatory system with more RBCs than normal, and therefore increases viscosity of the blood? Why is this a potential problem?
A large infusion of RBCs could increase the blood viscosity and bring about a decrease in cardiac output, decrease in blood flow velocity, and reduction in peripheral oxygen content. All of these would reduce aerobic capacity.
8. Imagine a person with an opening in the septum between their right and left ventricle. What would you predict would be different in their lungs, if anything? Explain.
The oxygenated blood would mix with the deoxygenated blood. Also, the volume of blood in the ventricles would change causing too much fluid in the lungs (pulmonary edema). The gas exchange would then be affected.
9. A patient is taking an inhibitor of smooth muscle contraction in order to lower blood pressure. How could this affect digestion and absorption? Explain.
The food in the stomach won’t be broken down as well because the inhibitor will make the contractions weaker. Less absorption will occur and the food will take longer to travel the length of the alimentary canal.
10. Imagine that you are testing the vital capacity of your lab partner and you measure a vital capacity of 400 ml. What specific changes in the lung might cause this?
Decrease surfactant inflammation of pleura damage to alveoli
11. What would you predict would happen in the pulmonary circuit when the air in the lung is low in O2 and high in CO2? Explain.
Respiratory failure is a condition in which not enough oxygen passes from the lungs into the blood or the lungs cannot properly remove carbon dioxide from the blood. The body will increase respiration in order to get CO2 out and more O2 back in.
12. Imagine a patient with a liver tumor composed of cells that secrete much, MUCH more glycoprotein into the blood. How and why would that affect (A) pressure in arteries, capillaries, and veins in the systemic and pulmonary circuits (B) cardiac output (C) the lymphatic system (D) body pH. Explain.
(A) More glycoprotein in the blood would increase the blood pressure
because the heart would pump harder and would have more volume to force through the vessels.
(B) Higher blood pressure and thicker blood would cause decreased cardiac output.
(C) This could cause lymphedema, which is a condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system.
(D) This could cause acidosis = sugar acidity level would be increased because of more glycoprotein in the blood
13. Regarding pharmacokinetics, how can individual variation affect ADME? (address each component of ADME).
Each component can be affected by a number of factors such as gender, age, physical activity, and food/drug intake. Alcohol, for example, can affect the ADME of certain drugs:
• Absorption: alcohol increases flow in the GI tract which causes an increase in the rate of drug absorption
• Distribution: alcoholics typically have low levels of albumin in the blood which can cause an increase in distribution of certain drugs
• Metabolism: alcohol is metabolized in the liver; it can inhibit liver enzymes to metabolize some drugs
• Elimination: alcohol has been found to increase the rate of drug elimination in alcoholics
14. It is said: “No T cells, no immunity”. Explain this statement.
Helper T cells are used to activate 95% of the B cell population and are necessary for activation of cytotoxic T cells. If the processing of pre-T cells and mature T cells does not occur, a portion of the immune system is absent and 95% of B cells can’t produce antibodies.
15. Explain why patients with impaired renal function might be anemic.
The kidneys produce a hormone (EPO) which stimulates the production of RBCs (carriers of hemoglobin). A patient whose kidneys are impaired would produce less EPO which leads to decreased production of RBCs that carry hemoglobin. This causes anemia.
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