What gland is located just superior to the kidneys?

Correct Answer: B

Rationale: Adrenal glands rest atop the kidneys, secreting cortisol, aldosterone, and epinephrine for stress, electrolyte balance, and fight-or-flight. The pituitary, brain-based, oversees hormones. The pancreas, abdominal, manages glucose. Ovaries, pelvic in females, produce sex hormones, not above kidneys. Adrenals' suprarenal position and diverse outputs distinguish them, essential for adrenal-renal interactions, unlike distant or unrelated glands.

Correct Answer: A

Rationale: Negative feedback regulates most hormones (e.g., cortisol inhibits ACTH), reducing secretion when levels suffice, maintaining homeostasis. Positive feedback (e.g., oxytocin in labor) amplifies, rare in endocrine control. Hormone-receptor complexes mediate effects, not regulation. Hormone-gene complexes influence steroid action, not feedback. Negative feedback's inhibitory loop distinguishes it, critical for stability, unlike amplifying or mechanistic options.

Correct Answer: B

Rationale: Hormone binding alters membrane permeability (e.g., ion channels), activates/inactivates enzymes (e.g., cAMP pathways), and stimulates mitosis (e.g., growth hormone) all typical. Cellular mutations, DNA damage events, aren't standard hormone effects. This absence distinguishes normal signaling, critical for physiological responses, contrasting with pathological changes.

Correct Answer: A

Rationale: Alpha cells secrete glucagon, targeting the liver to raise blood glucose via glycogenolysis and gluconeogenesis. Melatonin is pineal, calcitonin thyroid-derived, and glucagon's kidney role is secondary. Liver targeting distinguishes glucagon's function, vital for glucose homeostasis, contrasting with sleep or calcium regulators.

Correct Answer: B

Rationale: Drinking a liter of water dilutes blood, lowering osmolality; negative feedback reduces ADH to excrete water, increasing urine. Oxytocin isn't involved, and increased ADH would retain water. Decreased ADH distinguishes this response, critical for fluid regulation, contrasting with retention signals.