Nokea
ACTH stimulates the:
- A. hypothalamus to secrete corticotropin-releasing hormone (CRH).
- B. adenohypophysis to secrete cortisol.
- C. adrenal cortex to secrete cortisol.
- D. adrenal medulla to secrete glucagon.
Correct Answer: C
Rationale: The correct answer is C because ACTH (adrenocorticotropic hormone) stimulates the adrenal cortex to secrete cortisol. Step 1: ACTH is released from the anterior pituitary gland. Step 2: ACTH stimulates the adrenal cortex to produce and release cortisol. Choice A is incorrect because CRH is secreted by the hypothalamus to stimulate ACTH release. Choice B is incorrect because cortisol is produced in the adrenal cortex, not the adenohypophysis. Choice D is incorrect because the adrenal medulla secretes adrenaline and noradrenaline, not glucagon.
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Adrenaline can be used in the following EXCEPT:
- A. Allergic reactions
- B. Acute bronchial asthma
- C. Complete heart block
- D. Angina pectoris
Correct Answer: D
Rationale: Adrenaline is a sympathomimetic drug that acts on adrenergic receptors. In acute situations like allergic reactions, bronchial asthma, and heart block, adrenaline can be beneficial due to its bronchodilator and vasoconstrictor effects. However, in angina pectoris, which is caused by reduced blood flow to the heart muscle, the vasoconstrictor effect of adrenaline can worsen the condition by increasing the workload of the heart. Therefore, adrenaline should not be used in angina pectoris.
Which of the following could antagonize renal vasodilation induced by dopamine:
- A. Propranolol
- B. Atropine
- C. Prazosin
- D. Haloperidol
Correct Answer: D
Rationale: The correct answer is D: Haloperidol. Haloperidol is a dopamine receptor antagonist, which means it blocks dopamine receptors. Dopamine induces renal vasodilation by acting on dopamine receptors in the kidneys. Therefore, blocking these receptors with haloperidol would antagonize the renal vasodilation effect of dopamine.
A: Propranolol is a beta-blocker that acts on beta receptors, not dopamine receptors.
B: Atropine is a muscarinic antagonist and does not affect dopamine receptors.
C: Prazosin is an alpha-1 adrenergic antagonist and does not target dopamine receptors.
What two effects does PTH exert on the kidneys?
- A. Blocks sodium reabsorption and increases the excretion of water.
- B. Increases calcium reabsorption and increases the excretion of phosphate in the urine.
- C. Decreases the reabsorption of both calcium and phosphate.
- D. Increases the excretion of H+ and the excretion of bicarbonate.
Correct Answer: B
Rationale: The correct answer is B because PTH (Parathyroid Hormone) acts on the kidneys by increasing calcium reabsorption and increasing the excretion of phosphate in the urine. PTH stimulates the kidney to reabsorb more calcium to maintain normal blood calcium levels. It also enhances the excretion of phosphate in the urine, helping to lower blood phosphate levels. Option A is incorrect because PTH does not block sodium reabsorption or increase water excretion in the kidneys. Option C is incorrect as PTH does not decrease the reabsorption of both calcium and phosphate. Option D is incorrect because PTH does not increase the excretion of H+ or bicarbonate.
Identify a gland that is controlled by an anterior pituitary hormone.
- A. pancreas
- B. parathyroid
- C. adrenal medulla
- D. ovary
Correct Answer: D
Rationale: The correct answer is D: ovary. The anterior pituitary gland secretes follicle-stimulating hormone (FSH) and luteinizing hormone (LH) that regulate the function of the ovaries. FSH stimulates the growth of ovarian follicles, while LH triggers ovulation and stimulates the production of progesterone and estrogen. The pancreas (A) is mainly controlled by insulin and glucagon from the pancreas itself. The parathyroid gland (B) is regulated by parathyroid hormone (PTH) secreted by the parathyroid glands. The adrenal medulla (C) is controlled by the sympathetic nervous system, not by anterior pituitary hormones.
What medication is used with thyrotoxicosis to block the effects of the sympathetic nervous stimulation of the thyroid hormones?
- A. Potassium iodide
- B. Propylthiouracil (PTU)
- C. Atenolol (Tenormin)
- D. Radioactive iodine (RAI)
Correct Answer: C
Rationale: Atenolol is a beta-blocker that helps control the sympathetic nervous system effects of thyrotoxicosis, such as tachycardia and hypertension.