This is Not a Function of Insulin

Correct Answer: C

Rationale: The correct answer is C: Gluconeogenesis is not a function of insulin. Insulin's main role is to lower blood glucose levels by promoting glucose uptake and storage. Gluconeogenesis is the process of synthesizing glucose from non-carbohydrate sources, such as amino acids and glycerol, to increase blood glucose levels. Insulin inhibits gluconeogenesis by suppressing the enzymes involved in this process. Choices A, B, and D are all functions of insulin: A) Decreasing glycogenolysis - insulin promotes glycogen synthesis by inhibiting glycogen breakdown, B) Lipogenesis - insulin enhances the conversion of excess glucose into fatty acids for storage, and D) Glycogenesis - insulin increases the formation of glycogen from glucose for storage.

Correct Answer: C

Rationale: The correct answer is C because lipid-soluble hormones can freely diffuse through cell membranes to interact with intracellular receptors, leading to changes in gene expression. This mechanism is characteristic of lipid-soluble hormones, such as steroid hormones. Choice A is incorrect because lipid-soluble hormones are not constantly produced in the anterior pituitary gland. Choice B is incorrect as lipid-soluble hormones are hydrophobic, not hydrophilic, and are often transported bound to carrier proteins in the blood. Choice D is incorrect because lipid-soluble hormones are not formed from amino acids; rather, they are derived from cholesterol or similar compounds.

Correct Answer: D

Rationale: The correct answer is D, submandibular glands, as they produce the majority of salivary volume. These glands are the largest of the major salivary glands and secrete saliva rich in enzymes and mucin, contributing significantly to the total saliva volume. The lingual glands (A) are minor salivary glands located in the tongue and contribute a small portion of saliva. The sublingual glands (B) are also minor salivary glands located beneath the tongue, producing a smaller volume compared to the submandibular glands. The parotid glands (C) are another major salivary gland, but they produce a lesser volume of saliva compared to the submandibular glands.

Correct Answer: C

Rationale: Rationale: Gastrin secretion is primarily stimulated by luminal peptides and vagal discharge, which promote gastric acid secretion. Luminal acid, on the other hand, inhibits gastrin release as it acts as a negative feedback mechanism to regulate acid production. Phenylalanine does not directly stimulate gastrin secretion. Therefore, the correct answer is C as luminal acid inhibits, not stimulates, gastrin release. The other choices are incorrect because luminal peptides and vagal discharge are known stimulants of gastrin secretion, while phenylalanine does not have a direct effect on gastrin release.

Correct Answer: A

Rationale: The correct answer is A because gastrin primarily stimulates gastric acid secretion and gastric motility, not insulin secretion. Gastrin is released in response to the presence of food in the stomach, leading to increased gastric acid production and motility to aid in digestion. Insulin secretion is mainly regulated by glucose levels in the blood and hormones like insulin and glucagon. Therefore, the stimulation of insulin secretion after a carbohydrate meal is not a direct action of gastrin. Choices B, C, and D are incorrect because they accurately describe the actions of gastrin in the digestive system.