Nokea
Alison is being treated for hyperthyroidism. In reviewing her laboratory results, the physician would expect to see:
- A. Diminished thyroid hormone.
- B. Elevated thyroid hormone.
- C. Diminished PTH.
- D. Elevated PTH.
Correct Answer: B
Rationale: Hyperthyroidism is characterized by elevated levels of thyroid hormones, such as T3 and T4, which are produced in excess in this condition.
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The secretion of which of the following would be least affected by a decrease in extracellular fluid volume?
- A. CRH
- B. Arginine vasopressin
- C. Dehydroepiandrosterone
- D. Estrogens
Correct Answer: D
Rationale: The correct answer is D: Estrogens. When extracellular fluid volume decreases, the body activates the renin-angiotensin-aldosterone system to retain water and sodium. Estrogen is not directly involved in regulating fluid balance, so its secretion would be least affected. CRH (choice A) stimulates the release of cortisol, which affects fluid balance. Arginine vasopressin (choice B) regulates water reabsorption in the kidneys. Dehydroepiandrosterone (choice C) is a precursor to sex hormones, including estrogen.
Insulin:
- A. binds to GLUT 1-5 receptors in the peripheral tissues
- B. deficiency results in increased gluconeogenesis
- C. has a plasma half-life of 2-3 hours
- D. is secreted by the pancreatic A cells
Correct Answer: B
Rationale: The correct answer is B because insulin deficiency leads to increased gluconeogenesis due to the lack of inhibition on glucose production. Choice A is incorrect as insulin binds to GLUT 4 receptors, not GLUT 1-5. Choice C is wrong because insulin's half-life is only a few minutes. Choice D is also inaccurate as insulin is secreted by pancreatic beta cells, not A cells.
The following drugs can depress the sympathetic activity EXCEPT:
- A. Clonidine
- B. Reserpine
- C. Phenylephrine
- D. Labetalol
Correct Answer: C
Rationale: The correct answer is C: Phenylephrine. Phenylephrine is a sympathomimetic drug that stimulates the sympathetic nervous system, leading to vasoconstriction and increased heart rate. In contrast, choices A, B, and D all work to depress sympathetic activity by different mechanisms. Clonidine is an alpha-2 adrenergic agonist that decreases sympathetic outflow. Reserpine inhibits the storage of norepinephrine, leading to decreased sympathetic activity. Labetalol is a non-selective beta blocker that blocks beta-adrenergic receptors, reducing sympathetic effects. Therefore, Phenylephrine is the only drug among the options that does not depress sympathetic activity.
Injecting cocaine may cause a hypertensive crisis or stroke, and if the cocaine is inhaled frequently, it may destroy the tissues in the nose. Which of the following best describes how cocaine causes these adverse effects?
- A. Blocks alpha adrenergic receptors
- B. Blocks muscarinic receptors for ACh
- C. Blocks reuptake of noradrenaline released from adrenergic nerves
- D. Depletes norepinephrine from adrenergic nerve endings
Correct Answer: C
Rationale: Cocaine blocks the reuptake of noradrenaline from adrenergic nerves, leading to excessive stimulation of adrenergic receptors. This causes increased blood pressure, which can result in a hypertensive crisis or stroke. Additionally, the vasoconstrictive effects of excess noradrenaline can lead to tissue damage in the nose when cocaine is inhaled frequently. Choices A and B are incorrect because cocaine does not directly block alpha adrenergic or muscarinic receptors. Choice D is incorrect because cocaine does not deplete norepinephrine from adrenergic nerve endings but rather increases its concentration by blocking reuptake.
Which of the following agents might mask the hypoglycemic reaction in treated diabetic patients?
- A. Beta-adrenergic agonists
- B. Alpha-adrenergic antagonists
- C. Alpha-adrenergic agonists
- D. Beta-adrenergic antagonists
Correct Answer: D
Rationale: The correct answer is D: Beta-adrenergic antagonists. Beta-blockers can mask the typical signs and symptoms of hypoglycemia such as tremors, palpitations, and sweating by inhibiting the adrenergic response to low blood sugar levels. Other choices (A, B, C) are incorrect as they do not have the same mechanism of action in masking hypoglycemic reactions in diabetic patients.