Indicate the expectorant with the reflex mechanism:

Correct Answer: B

Rationale: The correct answer is B: Derivatives of Ipecacuanha and Thermopsis. These substances stimulate the reflex mechanism of coughing, leading to increased mucus clearance from the airways. Mucolytics like Ambroxol (choice D) thin out mucus, while sodium benzoate (choice A) is a preservative and trypsin (choice C) is an enzyme and not an expectorant. Therefore, B is correct as it directly promotes the cough reflex for mucus expulsion.

Correct Answer: C

Rationale: The correct answer is C because digoxin actually has a shorter half-life than digitoxin. Digoxin has a half-life of approximately 36 hours, while digitoxin has a longer half-life of around 7 days. A: Digoxin is a mild inotrope, which means it increases myocardial contractility. B: Digoxin increases vagal tone, leading to a decrease in heart rate. D: Digoxin acts by inhibiting the Na+/K+ ATPase pump, resulting in increased intracellular calcium levels and improved contractility. Therefore, choices A, B, and D are true statements regarding cardiac glycosides.

Correct Answer: B

Rationale: The correct answer is B: GI disturbance. Nitrates and nitrites primarily affect the cardiovascular system by dilating blood vessels, leading to vasodilation and decreased cardiac workload. GI disturbances are not commonly associated with these drugs. A: Orthostatic hypotension, tachycardia, C: Throbbing headache, and D: Tolerance are all known side effects of nitrates and nitrites due to their cardiovascular effects.

Correct Answer: C

Rationale: To increase blood pressure in low cardiac output, positive inotropic drugs (Choice C) are used to improve the heart's contractility and increase cardiac output. Ganglioblockers (Choice A) block sympathetic activity, potentially worsening low cardiac output. Vasoconstrictors (Choice B) can increase blood pressure but may not address the underlying cause of low cardiac output. Diuretics (Choice D) reduce blood volume and may further decrease cardiac output. Therefore, Choice C is the correct option to address low cardiac output by improving heart function and increasing blood pressure.

Correct Answer: C

Rationale: The correct answer is C because the secretion of thyrotropin (TSH) is regulated by a negative feedback loop. When the concentration of thyroid hormones in the blood decreases, the hypothalamus signals the pituitary gland to release more TSH to stimulate the thyroid gland to produce more thyroid hormones. Conversely, when the thyroid hormone levels are high, TSH secretion is inhibited. Choices A and B are incorrect because the amount of iodine and thyroid hormones in the thyroid gland itself does not directly regulate TSH secretion. Choice D is incorrect as catecholamines do not directly influence TSH secretion.