What triggers 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 fatty acids and amino acids 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. Gastrin (A) stimulates acid secretion in the stomach. Secretin (B) stimulates the pancreas to release bicarbonate to neutralize stomach acid. Insulin (D) is a hormone that regulates blood sugar levels and does not play a role in bile release.

Correct Answer: C

Rationale: The correct answer is C: pepsin. Pepsin is an enzyme produced in the stomach that specifically breaks down proteins into peptides. Amylase (A) digests carbohydrates, lipase (B) digests fats, and sucrase (D) digests sucrose. Pepsin is the only enzyme among the choices that is responsible for digesting proteins, making it the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Small intestine. The small intestine is where most of the absorption of nutrients occurs due to its large surface area and presence of villi and microvilli. These structures increase the absorption capacity, allowing for efficient absorption of nutrients like carbohydrates, proteins, fats, vitamins, and minerals. The stomach primarily functions in the digestion of food through the action of stomach acid and enzymes, while the large intestine mainly absorbs water and electrolytes. The mouth is responsible for initial digestion through chewing and production of saliva but does not play a significant role in nutrient absorption.

Correct Answer: D

Rationale: The correct answer is D, Vitamin B12. The jejunum is not the main site for absorption of Vitamin B12; instead, it is absorbed in the terminal ileum. Glucose, amino acids, and fatty acids are primarily absorbed in the jejunum. Absorption of Vitamin B12 occurs in the ileum where it binds to intrinsic factor secreted by the stomach. Therefore, the jejunum is not the main site for absorption of Vitamin B12, making it the correct answer. Choices A, B, and C are incorrect because the jejunum is indeed the main site for absorption of glucose, amino acids, and fatty acids, respectively.

Correct Answer: C

Rationale: Rationale: The stomach primarily functions in digestion and does not have significant absorption capabilities. Glucose is absorbed in the small intestine through specialized transport mechanisms. Choices A (Ca) and D (aromatic amino acids) are primarily absorbed in the small intestine as well. Alcohol is absorbed in the stomach to a small extent, but the majority is absorbed in the small intestine. Therefore, the correct answer is C (Glucose) as it is primarily absorbed in the small intestine, not the stomach.