The regulation of sodium

A. Gastrin: G cells secrete gastrin, a hormone that stimulates parietal cells to produce hydrochloric acid and promotes gastric motility. It is released in response to food components like peptides, caffeine, and a rise in pH.
B. Pepsin: Pepsin is an enzyme that digests proteins, but it is secreted as pepsinogen by chief cells, not G cells.
C. Ghrelin: Ghrelin is a hunger-stimulating hormone, secreted primarily by cells in the stomach fundus, not by G cells.
D. Hydrochloric acid: Hydrochloric acid is secreted by parietal cells, not G cells.

A. Extrinsic controls will reduce blood plasma volume while intrinsic controls will increase blood plasma volumes: This is too simplistic. Both can influence fluid volume, but their primary goals differ.
B. Intrinsic controls raise blood pressure while extrinsic controls lower blood pressure: Intrinsic controls maintain GFR, not blood pressure; extrinsic controls (like RAAS and sympathetic input) raise BP.
C. Extrinsic and intrinsic controls work in nearly opposite ways: They serve different purposes rather than being true opposites.
D. Extrinsic controls have the greatest effect on systemic blood pressure while intrinsic controls have a greater effect on GFR: Intrinsic (renal autoregulation) maintains a constant GFR; extrinsic controls (like sympathetic nervous system and RAAS) maintain systemic blood pressure, especially during stress or blood loss.