Somatostatin is secreted from which islet cell?

Correct Answer: D

Rationale: Somatostatin is secreted by D (delta) cells in the pancreatic islets to regulate insulin and glucagon secretion.

Correct Answer: D

Rationale: Cholesterol inhibits HMG-CoA reductase, is esterified by ACAT, and downregulates LDL receptors via SREBP, making all statements true.

Correct Answer: C

Rationale: Glucose uses Na^+-dependent SGLT1 for luminal uptake; fructose uses GLUT5 (Na^+-independent). Absorption is mainly in the jejunum.

Correct Answer: D

Rationale: Osteoclasts originate from monocyte/macrophage lineage in bone marrow.

Correct Answer: C

Rationale: The pancreas acts as an endocrine gland, secreting insulin directly into the bloodstream, and an exocrine gland, secreting digestive enzymes through ducts.