The mineralocorticoids produced by the adrenal glands are produced within the?

Correct Answer: C

Rationale: Mineralocorticoids, primarily aldosterone, are synthesized in the adrenal cortex's zona glomerulosa, regulating sodium/potassium balance and blood pressure. Parafollicular cells (thyroid C-cells) produce calcitonin for calcium, not mineralocorticoids. Zona reticularis and fasciculata collaborate reticularis makes androgens, fasciculata glucocorticoids (e.g., cortisol), not mineralocorticoids, though some overlap exists. Zona glomerulosa's outer-layer specificity for aldosterone distinguishes it, critical for electrolyte homeostasis, unlike thyroid or other adrenal zones' roles.

Correct Answer: C

Rationale: Beta cells in pancreatic islets secrete insulin, lowering blood glucose by driving cellular uptake and glycogen storage. Delta cells release somatostatin, inhibiting other hormones. Alpha cells produce glucagon, raising glucose. 'Gamma' isn't a pancreatic cell type possibly a typo (Q4 lists 'beta' twice). Beta cells' insulin role distinguishes them, critical for glucose homeostasis, unlike inhibitory or glucose-elevating cells.

Correct Answer: A

Rationale: The thyroid controls BMR via T3/T4, increasing cellular energy use, setting resting metabolism. Parathyroid regulates calcium (PTH), not BMR. Testes produce testosterone, affecting muscle, not baseline metabolism. Pancreas (insulin/glucagon) manages glucose, not BMR directly. Thyroid's metabolic dominance distinguishes it, critical for energy homeostasis, unlike calcium, sex, or glucose regulators.

Correct Answer: B

Rationale: Calcitonin, from thyroid C-cells, lowers blood calcium by bone deposition, countering PTH. Adrenal cortex produces steroids (e.g., cortisol), not calcitonin. Pituitary regulates via TSH, not secreting calcitonin. Thymus releases thymosin for immunity. Thyroid's calcitonin role distinguishes it, key to calcium balance, unlike adrenal, pituitary, or immune glands.

Correct Answer: A

Rationale: Steroids, lipid-soluble, diffuse across membranes, enter nuclei, and activate genes for protein synthesis (e.g., cortisol effects). They don't catalyze cAMP peptide hormones do via membrane receptors and G-proteins. This limitation distinguishes steroid mechanisms, key to genomic actions, contrasting with second-messenger systems.