Which hormone stimulates the release of bile from the gallbladder?

Correct Answer: C

Rationale: The correct answer is C: Cholecystokinin. Cholecystokinin is a hormone released by the small intestine in response to the presence of fats in the duodenum. It stimulates the gallbladder to contract and release bile into the small intestine to aid in the digestion and absorption of fats. Secretin (A) stimulates the pancreas to release bicarbonate to neutralize acidic chyme. Insulin (B) regulates blood sugar levels, not bile release. Gastrin (D) stimulates the release of gastric acid in the stomach, not bile.

Correct Answer: B

Rationale: Bile does not contain potassium (K) as it is not a component of bile. The correct answer is B. Alkaline phosphatase is present in bile and aids in digestion. Cholesterol is also found in bile. CCK (Cholecystokinin) is a hormone released by the small intestine to stimulate bile release. Potassium is not a part of the composition of bile.

Correct Answer: A

Rationale: The correct answer is A. Peristalsis involves coordinated waves of muscle contractions that propel food forward. However, peristalsis can also involve backward movements to help with mixing and digestion. Therefore, the statement that peristalsis only involves forward movements is incorrect. Segmentation involves mixing and breaking down food through contractions that occur in non-unidirectional patterns. Peristalsis can be found in the esophagus, stomach, and intestines, while segmentation is mainly present in the small intestine. Therefore, choices B, C, and D are incorrect based on the explanations provided.

Correct Answer: C

Rationale: Infarction of the bowel may be caused by a volvulus, where the bowel twists on its mesentery, leading to compromised blood flow. Mesenteric artery thrombosis can also cause bowel infarction by obstructing blood supply. Therefore, the correct answer is C (both). Choices A and B are incorrect because each of them individually can cause bowel infarction.

Correct Answer: B

Rationale: The correct answer is B: Sodium-glucose co-transport system. This system involves the active transport of glucose across the small intestine epithelial cells with the help of sodium ions. This mechanism allows for the absorption of glucose against its concentration gradient, ensuring efficient uptake. Other choices are incorrect because: A) Simple passive diffusion is not efficient for glucose absorption due to its hydrophilic nature. C) Osmosis is the movement of water molecules, not glucose. D) Primary active transport involves the direct use of energy to transport molecules, which is not the case for glucose absorption in the small intestine.