How many hormones are produced by the posterior pituitary?

Correct Answer: A

Rationale: The posterior pituitary produces zero hormones it stores and releases ADH and oxytocin, synthesized by hypothalamic neurons, via the hypothalamic-hypophyseal tract. 'One' or 'two' suggest production (e.g., ADH, oxytocin), but neurohypophysis lacks glandular synthesis, unlike anterior pituitary (e.g., TSH). 'Three' exceeds known outputs no third hormone exists. Its role as a neural extension for hypothalamic hormones distinguishes it, key to understanding pituitary division, unlike hormone-generating glands.

Correct Answer: D

Rationale: Gigantism, acromegaly, and hyperprolactinemia often stem from pituitary adenomas (tumors), but the question implies adrenal tumors (pheochromocytoma, neuroblastoma) from context. These pituitary conditions aren't adrenal tumors, so 'none' fits if strictly adrenal-focused. This distinction clarifies tumor location, key to differential diagnosis, contrasting with pituitary-derived states.

Correct Answer: B

Rationale: The pineal gland secretes melatonin, peaking in darkness to regulate circadian rhythms like sleep-wake cycles, influenced by retinal light signals. The thymus matures T-cells, not rhythms. Parathyroids control calcium via PTH, not timekeeping. The pituitary, a master gland, doesn't directly manage circadian cycles hypothalamus does via pineal. Pineal's melatonin-driven role distinguishes it, key to biological timing, unlike immune, calcium, or regulatory glands.

Correct Answer: A

Rationale: Thyroid's calcitonin lowers blood calcium, depositing it in bones, while parathyroid hormone (PTH) raises it, mobilizing bone calcium and kidney reabsorption. Reversing this (PTH lowering, calcitonin raising) defies physiology. T3/T4 (thyroxine, triiodothyronine) regulate metabolism, not calcium. Including all thyroid hormones (T3, T4, calcitonin) with PTH overstates only calcitonin pairs with PTH. This antagonistic balance distinguishes calcium regulation, key to skeletal and blood homeostasis.

Correct Answer: B

Rationale: Parathyroid glands regulate blood calcium, raising it via PTH (bone resorption, kidney reabsorption), while thyroid's calcitonin lowers it parathyroid dominates setpoint. Thyroid contributes (calcitonin), but parathyroid drives adjustment. Posterior pituitary (ADH) manages water, not calcium. Adrenal medulla (epinephrine) affects stress, not calcium. Parathyroid's PTH primacy distinguishes it, critical for calcium homeostasis, unlike secondary or unrelated glands.