Which of the following is not true with melatonin?

Correct Answer: C

Rationale: Melatonin, from the pineal gland, regulates sleep-wake cycles, peaking in darkness to induce sleep, reducing arousal and cortisol darkness triggers, light inhibits it. The false statement reverses this: light suppresses melatonin, resetting circadian rhythms, while darkness stimulates it. Heat loss and rhythm regulation are true effects; pineal production is accurate. This light-dark dynamic distinguishes melatonin's role, critical for circadian alignment, unlike inverted or correct functions.

Correct Answer: A

Rationale: Endocrine glands (e.g., thyroid) are ductless, releasing hormones into blood for distant targets, while exocrine glands (e.g., sweat) use ducts to surfaces or cavities. Hormones versus waste oversimplifies exocrine products (e.g., saliva) aren't just waste. Both gland types are epithelial, not connective for exocrine. Interconnection isn't universal endocrine glands (e.g., adrenals) act independently, like exocrine. Ductless blood delivery distinguishes endocrine function, key to systemic reach, unlike ducted or mischaracterized traits.

Correct Answer: C

Rationale: The posterior pituitary stores and releases oxytocin (labor, lactation) and ADH (water balance), both hypothalamic-made. Growth hormone and prolactin are anterior pituitary products, not stored posteriorly. Prolactin isn't posterior oxytocin fits. ADH with GH mixes lobes incorrectly. Oxytocin-ADH pairing distinguishes neurohypophyseal function, critical for hypothalamic delivery, unlike anterior hormones.

Correct Answer: C

Rationale: Parathyroid hormone (PTH) comes from parathyroid glands, regulating calcium, not anterior pituitary. GH (growth), FSH (reproduction), and TSH (thyroid) are anterior pituitary hormones, driving target glands. PTH's external origin distinguishes it, key to its independent role, unlike pituitary tropic hormones.

Correct Answer: D

Rationale: Excess pituitary growth hormone post-puberty, when epiphyseal plates are closed, causes acromegaly bone thickening, not height increase (gigantism, pre-closure). Tetany is calcium-related, kidney failure unrelated. Acromegaly's post-growth distinction is key, critical for diagnosing pituitary disorders, contrasting with pre-pubertal effects.