When norepinephrine is used as a hormone, it is released by which of the following structures?

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: C

Rationale: Pancreas, near the small intestine in the abdomen, secretes insulin/glucagon glucose regulation. Adrenals are above kidneys, not near intestine. Hypothalamus is cranial, not abdominal. Thyroid is cervical, metabolic. Pancreas' abdominal proximity distinguishes it, critical for digestion and metabolism, unlike suprarenal, brain, or neck glands.

Correct Answer: C

Rationale: ADH deficiency causes diabetes insipidus polyuria/polydipsia from poor water reabsorption, dilute urine. Diabetes mellitus is insulin-related, glucose-driven. Uterine contractions tie to oxytocin, not ADH. Decreased urine opposes DI volume rises. DI's water loss distinguishes it, key to ADH's role, unlike glucose, contraction, or retention conditions.

Correct Answer: B

Rationale: Simple goiter (thyroid enlargement) from iodine deficiency is prevented by dietary iodine enables T3/T4 synthesis, avoiding compensatory growth. Antibiotics treat infection, not deficiency. Surgery removes goiter, not prevents. Hormone therapy (e.g., levothyroxine) treats hypothyroidism, not root cause. Iodine addition distinguishes prevention, key to thyroid health, unlike infection, surgical, or replacement approaches.

Correct Answer: C

Rationale: Adrenal medulla, inner gland portion, is nervously controlled (sympathetic), producing epinephrine/norepinephrine fight-or-flight. Glucose/mineral regulation is adrenal cortex (cortisol, aldosterone), not medulla distinct roles. Medulla's neural-catecholamine function distinguishes it, key to acute stress, unlike cortex's metabolic/electrolyte tasks.