Which enzyme is responsible for digesting carbohydrates?

Correct Answer: B

Rationale: The correct answer is B: amylase. Amylase is responsible for digesting carbohydrates by breaking down starches into simple sugars. Pepsin (A) digests proteins, lipase (C) digests fats, and trypsin (D) digests proteins as well. Amylase specifically targets carbohydrates, making it the correct enzyme for this function.

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: D

Rationale: The correct answer is D: The small intestine has segmentation contractions. This is because segmentation contractions are responsible for mixing and moving chyme (partially digested food) along the small intestine, allowing for optimal nutrient absorption. This process helps maximize the contact between chyme and the intestinal walls, facilitating absorption. A: Incorrect. The small intestine does not store food for several hours; instead, it continuously processes and absorbs nutrients. B: Incorrect. While the small intestine plays a crucial role in digestion and absorption, the main source of digestive enzymes is the pancreas. C: Incorrect. Haustrae are found in the large intestine, not the small intestine. They aid in the absorption of water and electrolytes.

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.