Which of the following statements regarding pituitary hormones is false?

Correct Answer: B

Rationale: The hypothalamus synthesizes oxytocin and ADH, stored in the posterior pituitary true. Luteinizing hormone (LH) triggers ovulation and progesterone/estrogen production true. FSH/LH hyposecretion causes sterility true. ADH, however, reduces urine volume by increasing water reabsorption, raising blood volume, not decreasing it making B false. This error distinguishes ADH's role in osmoregulation, critical for fluid balance, contrasting with diuretic effects.

Correct Answer: A

Rationale: The endocrine and nervous systems regulate body functions: endocrine via hormones (slow, widespread), nervous via neurons (fast, specific). Immune defends, circulatory transports, respiratory oxygenates supportive, not regulatory. This dual control distinguishes them, key to coordination, contrasting with protective or transport systems.

Correct Answer: D

Rationale: Adrenocorticotropic hormone (ACTH) from the anterior pituitary stimulates adrenal cortisol release, managing stress/metabolism. Aldosterone (adrenal) and angiotensin (RAAS) regulate fluid, ADH controls water not cortisol. ACTH's specific role distinguishes it, key to the HPA axis, contrasting with fluid-regulating hormones.

Correct Answer: C

Rationale: The pancreas secretes insulin and glucagon to maintain blood sugar: insulin lowers it by promoting uptake, glucagon raises it via liver glucose release. Pineal (melatonin), pituitary (GH, ACTH), and adrenal (adrenaline) glands affect metabolism indirectly not sugar directly. Pancreas's dual hormonal role distinguishes it, key to glucose homeostasis, contrasting with stress or growth regulators.

Correct Answer: C

Rationale: Insulin, from pancreatic β-cells, is synthesized as proinsulin, cleaved to active form, lowering glucose via membrane receptors (tyrosine kinase). α-cells secrete glucagon, not insulin. It's a dual-chain polypeptide, not triple helical structural misfit. It binds surface receptors, not cytoplasmic steroids do that. Prohormone synthesis distinguishes insulin's production, critical for its activation and glucose regulation, unlike wrong cell origin, structure, or receptor location.