Aldosterone ________.

Correct Answer: B

Rationale: The correct answer is B: Aldosterone functions to increase sodium reabsorption. Aldosterone is a hormone produced by the adrenal glands that acts on the kidneys to enhance the reabsorption of sodium and water and excretion of potassium. This helps regulate blood pressure and electrolyte balance. The other choices are incorrect because: A: Aldosterone is not secreted by the neurohypophysis, but by the adrenal glands. C: Aldosterone actually decreases potassium concentration in the blood. D: Aldosterone production is primarily regulated by the renin-angiotensin-aldosterone system, not greatly influenced by ACTH.

Correct Answer: A

Rationale: The correct answer is A. Alcohol suppresses the secretion of ADH (antidiuretic hormone), which leads to a decrease in the reabsorption of water from the kidneys. ADH is responsible for increasing water reabsorption, so suppressing it results in more water being excreted. Choices B, C, and D are incorrect because alcohol does not affect aldosterone secretion, and aldosterone primarily regulates sodium reabsorption rather than water reabsorption. ADH is the hormone directly involved in water reabsorption in the kidneys, making choice A the correct answer.

Correct Answer: B

Rationale: The correct answer is B: adding iodine to the diet. Iodine deficiency is a common cause of simple goiter. Iodine is essential for the production of thyroid hormones, and a lack of it can lead to the enlargement of the thyroid gland. Adding iodine to the diet helps prevent simple goiter by ensuring the thyroid has enough iodine to function properly. Antibiotics (choice A) are not effective for preventing goiter as it is not caused by bacteria. Surgery (choice C) and hormone therapy (choice D) are typically used to treat goiter once it has developed, not prevent it.

Correct Answer: D

Rationale: The correct answer is D because aldosterone actually causes an increase in blood pressure by promoting sodium and water retention in the kidneys. This leads to an expansion of blood volume and subsequently an increase in blood pressure. Choices A, B, and C are incorrect because aldosterone does indeed target kidney tubules to absorb sodium and water, it is a mineralocorticoid hormone, and it causes a decrease in urine volume due to its role in water and sodium reabsorption in the kidneys.

Correct Answer: D

Rationale: The correct answer is D, Both A and C. Melatonin from the pineal gland regulates sleep-wake cycles (A) by influencing the body's internal clock. It also plays a role in sexual development (C) by influencing the release of reproductive hormones. Other choices, B (water balance), are regulated by hormones like ADH and aldosterone, not melatonin. The correct answer encompasses the functions of melatonin in both sleep regulation and sexual development.