The acidophils of the anterior pituitary secrete:

Correct Answer: A

Rationale: Acidophils in the anterior pituitary secrete prolactin (lactation) and growth hormone (GH, growth/metabolism), staining pink with acidic dyes. LH and FSH, gonadotropins, come from basophils, as does TSH (thyroid stimulation). MSH (melanocyte-stimulating) is minimal in humans, from intermediate lobe, not acidophils. Prolactin and GH's acidophil origin distinguishes them, critical for lactation and growth, unlike basophil hormones.

Correct Answer: C

Rationale: The posterior pituitary releases two hormones antidiuretic hormone (ADH) and oxytocin produced by hypothalamic neurons and transported via axons. It doesn't synthesize hormones itself, unlike the anterior pituitary (e.g., six hormones). 'Zero' ignores storage/release, and 'six' overestimates. This dual role distinguishes posterior pituitary function, key to water balance and reproduction, contrasting with anterior synthesis.

Correct Answer: A

Rationale: Chromaffin cells in the adrenal medulla secrete catecholamines (epinephrine, norepinephrine) for fight-or-flight responses, derived from neural crest cells. Neuroglial cells support neurons, follicle cells are thyroid-specific, and oxyphil cells are in parathyroids. Chromaffin cells' neuroendocrine role distinguishes them, key to rapid stress responses, contrasting with supportive or other glandular cells.

Correct Answer: B

Rationale: Insulin lowers blood glucose by binding receptors, triggering GLUT4 transporters to move to cell membranes, enhancing uptake. It doesn't transport glucose, breaks glycogen (glucagon does), or act renally (reabsorption is passive). Facilitating transporter movement distinguishes insulin's mechanism, key to glucose regulation, contrasting with glycogenolysis or renal roles.

Correct Answer: C

Rationale: Neural stimuli, like stress from a car accident, activate the adrenal medulla via sympathetic nerves, releasing epinephrine for pupil dilation, heart rate increase, and rapid breathing classic fight-or-flight. Humoral stimuli respond to blood changes (e.g., PTH to low Ca²⁺). Hormonal stimuli involve hormones triggering others (e.g., TSH for thyroid). Positive feedback amplifies (e.g., oxytocin in labor), not acute stress. Neural triggering distinguishes this rapid endocrine response, key to sympathetic-endocrine integration, unlike blood-based or cascading stimuli.