A person with untreated iodine-deficiency goiter has a high:

Correct Answer: A

Rationale: Untreated iodine-deficiency goiter raises TSH secretion low iodine cuts thyroxine (Tâ‚„), prompting pituitary TSH increase to stimulate the thyroid, enlarging it. Thyroxine drops, not rises, due to iodine lack. Temperature and metabolic rate fall (hypothyroidism), not rise, from low Tâ‚„. TSH's compensatory surge distinguishes it, key to goiter's feedback loop, unlike reduced thyroid output or metabolic effects.

Correct Answer: B

Rationale: The hypothalamus connects to the posterior pituitary via nerve axons in the hypothalamohypophyseal tract. These axons transport antidiuretic hormone (ADH) and oxytocin, synthesized in hypothalamic neurons, for release. Blood vessels link the anterior pituitary, not posterior, while cartilage and bone are structural, not functional connectors. This axonal bridge distinguishes posterior pituitary control, key to neurohormone secretion in fluid and reproductive regulation.

Correct Answer: B

Rationale: Hyperparathyroidism, excess PTH, overstimulates osteoclasts, weakening bones and risking fractures by elevating blood calcium. Bone deposition decreases, and convulsions may occur from hypocalcemia (opposite condition), not hypercalcemia. 'All' is incorrect. Fractures distinguish this pathology, key to diagnosing skeletal effects of prolonged PTH elevation, contrasting with deposition or neurological symptoms.

Correct Answer: A

Rationale: Human placental lactogen (hPL), from the placenta, prepares breasts for lactation by stimulating mammary growth and shifts maternal metabolism to favor fetal nutrition. It doesn't nourish the placenta or regulate menstruation (absent in pregnancy). 'All' is incorrect. Breast preparation distinguishes hPL's role, vital for postpartum milk production, contrasting with placental or cycle functions.

Correct Answer: C

Rationale: Endocrine glands secrete hormones, chemical messengers, into the bloodstream for distant target organs, like thyroid releasing thyroxine to regulate metabolism systemically. Duct transport defines exocrine glands (e.g., sweat, sebaceous), not endocrine hormones bypass ducts. Neurotransmitters in synaptic clefts are neural, not glandular, actions (e.g., acetylcholine at synapses). Sebaceous and sweat glands are exocrine, releasing sebum or sweat externally, not hormones internally. Bloodstream delivery distinguishes endocrine function, key to their regulatory role across tissues, unlike localized or external secretions.