Glucagon

Correct Answer: B

Rationale: Rationale: Glucagon stimulates the breakdown of glycogen stored in the liver into glucose, increasing blood glucose levels. This process, called glycogenolysis, is crucial during times of low blood sugar to maintain energy levels. Therefore, choice B is correct. Choices A, C, and D are incorrect because glucagon does not directly affect protein synthesis within cells, decrease glycogen conversion into glucose, or slow down glucose formation from lactic acid.

Correct Answer: C

Rationale: Step-by-step rationale for choice C being correct: 1. Oligosaccharidase deficiency impairs breakdown of oligosaccharides in the small intestine. 2. Undigested oligosaccharides draw water into the intestines, causing osmotic diarrhea. 3. This leads to increased fluid content in the stool, resulting in osmotic diarrhea. 4. This process does not involve salivary amylase or lactose intolerance.

Correct Answer: B

Rationale: Chief cells in the gastric glands of the stomach secrete pepsinogen. Pepsinogen is an inactive precursor of pepsin, which is an enzyme responsible for breaking down proteins. This process aids in the digestion of proteins in the stomach. Chief cells do not secrete HCl (A), which is secreted by parietal cells. Intrinsic factor (C) is secreted by parietal cells and is essential for vitamin B12 absorption, not by chief cells. HCO3- (D) is secreted by the pancreas to neutralize stomach acid in the duodenum, not by chief cells in the stomach.

Correct Answer: C

Rationale: The correct answer is C: GIP. GIP, or glucose-dependent insulinotropic peptide, is the most important hormone in insulin secretion. It is released by the intestines in response to glucose intake, stimulating the release of insulin from the pancreas. Gastrin (A) is involved in gastric acid secretion, not insulin. CCK (B) and secretin (D) are involved in digestion and pancreatic enzyme secretion, not insulin regulation. So, GIP is the correct answer as it directly stimulates insulin release in response to glucose levels.

Correct Answer: D

Rationale: The correct answer is D. Thyroxine is deiodinated in the liver to T3, so approximately 33% of thyroxine is converted to the more active form, triiodothyronine. This conversion is important for regulating metabolic processes in the body. Choices A and C are incorrect because thyroxine is primarily bound to thyroxine-binding globulin in the plasma, not albumin, and it does not stimulate TSH release. Choice B is incorrect because T3 is actually more potent than thyroxine, not the other way around.