ATI RN
Endocrine System Questions Questions
Question 1 of 5
The production of melatonin is inhibited by
Correct Answer: B
Rationale: Melatonin production by pinealocytes rises in darkness and is inhibited by bright light, detected by retinal-suprachiasmatic pathways, suppressing synthesis. Declining light boosts it, serotonin is a precursor (not inhibitor), and pinealocyte activity drives production. Light's inhibitory effect distinguishes melatonin regulation, key to sleep timing, contrasting with darkness-driven increase.
Question 2 of 5
If an autoimmune disorder targets the alpha cells, production of which hormone would be directly affected?
Correct Answer: D
Rationale: Alpha cells in the pancreatic islets produce glucagon, raising blood glucose via glycogenolysis. An autoimmune attack on them directly reduces glucagon. Somatostatin, from delta cells, inhibits other hormones. Pancreatic polypeptide, from PP cells, regulates digestion. Insulin, from beta cells, lowers glucose type 1 diabetes targets beta, not alpha. Glucagon's alpha-cell origin distinguishes it, key to glucose counterregulation, unlike other islet hormones affected indirectly.
Question 3 of 5
Part of the effect of growth hormone is influenced by a group of protein chemical signals called:
Correct Answer: A
Rationale: Somatomedin-C (IGF-1), a liver-derived protein induced by growth hormone (GH), mediates GH's anabolic effects, promoting bone and muscle growth. Gonadotropins (FSH, LH) target gonads, not GH pathways. Prostaglandins regulate inflammation and smooth muscle, not growth. Prolactin drives lactation, not GH effects. Somatomedin-C's role as GH's effector distinguishes it, key to childhood growth and adult anabolism, unlike reproductive, inflammatory, or lactation signals.
Question 4 of 5
Which of the following statement is true?
Correct Answer: A
Rationale: Acromegaly, from pituitary GH excess post-puberty, causes bone thickening true. Addison's affects adrenals, not thyroid; hypothyroidism (low T3/T4) is true but not sole correct; Simmond's is pituitary, not adrenal. Acromegaly's pituitary origin distinguishes it, key to endocrine classification, though C is also true, A matches provided answer.
Question 5 of 5
Which of these is not an endocrine property?
Correct Answer: C
Rationale: Rapid-acting effects typify neural responses (e.g., milliseconds), not endocrine, where hormones travel via blood (e.g., insulin), causing slow, cyclic changes (e.g., menstrual cycle) via chemical signals. Blood transport enables systemic action, slow effects reflect diffusion and receptor binding, and chemicals (hormones) drive outcomes rapid action contradicts this, distinguishing neural speed from endocrine's prolonged regulation, critical for their distinct roles.