The nurse reviews the function of thyroid gland hormones. What is the primary function of calcitonin?

Correct Answer: D

Rationale: The primary function of calcitonin is to regulate calcium and phosphorus balance in the body. Calcitonin works to decrease blood calcium levels by inhibiting bone breakdown and increasing calcium excretion by the kidneys. This helps maintain the overall balance of calcium and phosphorus in the body. Choices A, B, and C are incorrect as they do not align with the known function of calcitonin. Sodium and potassium balance, magnesium balance, and norepinephrine balance are not directly influenced by calcitonin.

Correct Answer: B

Rationale: The correct answer is B: Postural hypotension. Terazosin is an alpha-1 blocker used to treat hypertension and BPH. Postural hypotension is a common side effect due to vasodilation, causing a sudden drop in blood pressure when changing positions. This side effect can lead to dizziness, fainting, and falls, especially in elderly patients. Bronchospasm (A) is not a common side effect of terazosin. Heart failure (C) is not a typical side effect and is unlikely with proper monitoring. Sedation (D) is not a significant side effect of terazosin.

Correct Answer: C

Rationale: The correct answer is C: Amphetamine. Amphetamine is not a catecholamine because it is a synthetic drug, not naturally produced by the body like adrenaline (A), noradrenaline (B), and isoprenaline (D). Catecholamines are a class of neurotransmitters that include dopamine, adrenaline, and noradrenaline, all of which have a catechol group in their chemical structure. Amphetamine, on the other hand, is a substituted phenethylamine with no catechol group. This distinction makes amphetamine the only non-catecholamine among the given options.

Correct Answer: D

Rationale: The correct answer is D: Stimulate muscarinic receptors. Parasympathomimetic drugs mimic the actions of the parasympathetic nervous system, which primarily uses acetylcholine on muscarinic receptors to produce its effects. By stimulating muscarinic receptors, these drugs enhance parasympathetic activity. A, B, and C are incorrect: A: Inhibiting muscarinic receptors would have the opposite effect of parasympathomimetic drugs. B: Inhibiting the release of acetylcholine would also reduce parasympathetic activity. C: Inhibiting adrenergic receptors pertains to the sympathetic nervous system, not the parasympathetic system targeted by parasympathomimetic drugs.

Correct Answer: B

Rationale: The correct answer is B: Trimetaphan. Nicotinic receptors are blocked by non-depolarizing neuromuscular blockers like Trimetaphan. Propranolol (A) is a beta-blocker, Prazosin (C) is an alpha-1 blocker, and Pilocarpine (D) is a muscarinic agonist, none of which block nicotinic receptors. Therefore, Trimetaphan (B) is the only choice that directly blocks nicotinic receptors.