ATI RN
Endocrine System Questions Questions
Question 1 of 5
What stimulates the release of PTH from the parathyroid gland?
Correct Answer: D
Rationale: Low blood calcium triggers parathyroid hormone (PTH) release to raise levels via bone resorption and kidney action. High calcium inhibits, TSH targets thyroid, calcitonin (thyroid-made) lowers calcium. Low calcium stimulus distinguishes PTH regulation, critical for calcium homeostasis, contrasting with inhibitory or unrelated signals.
Question 2 of 5
with regard to thyroid physiology
Correct Answer: C
Rationale: T4 (thyroxine) is synthesized from tyrosine in thyroglobulin within thyroid follicles, iodinated to form T3/T4, released to boost metabolism. Metabolism occurs mainly in liver/kidneys, not spleen/bone marrow. T3/T4 act via nuclear receptors, not identical membrane ones T3 is more potent. T4 isn't more active converted to T3 for greater effect. Thyroglobulin's role as a precursor scaffold distinguishes T4 synthesis, key to thyroid hormone production, unlike incorrect metabolism sites, receptor action, or potency claims.
Question 3 of 5
With regard to adrenal function
Correct Answer: B
Rationale: Adrenal medulla, secreting epinephrine/norepinephrine, isn't essential life persists post-adrenalectomy with cortical steroids. Zona fasciculata secretes cortisol, not aldosterone (glomerulosa). ACTH mainly controls cortisol, not glomerulosa's aldosterone (angiotensin II does). Medullary secretion is ~80% epinephrine, not norepinephrine. Non-essentiality distinguishes medulla, key to understanding adrenal roles, unlike zonal, control, or output errors.
Question 4 of 5
Which is false
Correct Answer: B
Rationale: Free cortisol feeds back negatively on both pituitary (ACTH) and hypothalamus (CRH) false to exclude hypothalamus. Suprachiasmatic nuclei drive ACTH's diurnal rhythm. Haemorrhage boosts aldosterone (RAAS) and cortisol (stress). Testosterone inhibits LH. Hypothalamic feedback distinguishes cortisol's regulation, key to HPA axis, unlike rhythm, stress, or gonadal truths.
Question 5 of 5
Concerning Ca metabolism
Correct Answer: A
Rationale: PTH decreases serum PO₄ by increasing renal excretion, raising Ca²⺠net effect is PO₄ reduction. Vitamin D increases Ca/PO₄ absorption, reducing excretion opposite claim. Calcitonin is from thyroid C-cells, not parathyroid. Insulin promotes bone formation (anabolic), not decreases. PTH's PO₄-lowering distinguishes it, key to calcium-phosphate regulation, unlike vitamin D, calcitonin, or insulin errors.