Which of the following stimuli activates sensors in the walls of digestive organs?

Correct Answer: D

Rationale: The correct answer is D, all of the above. 1. Breakdown products of digestion activate chemoreceptors in the digestive organs. 2. Distension triggers stretch receptors in the walls of the organs. 3. pH of chyme stimulates pH receptors. 4. All three stimuli work together to regulate and coordinate digestive processes. Therefore, D is correct as all options activate sensors in the walls of digestive organs. Choice A is incorrect because it only refers to chemoreceptors, overlooking the other types of receptors involved. Choice B is incorrect as it only mentions distension, omitting the roles of chemical stimuli. Choice C is incorrect as it solely focuses on pH receptors, neglecting the other types of sensors involved in digestion.

Correct Answer: A

Rationale: The correct answer is A: pancreas. The pancreas is an accessory organ of digestion because it produces digestive enzymes that help break down carbohydrates, fats, and proteins in the small intestine. It also secretes bicarbonate to neutralize stomach acid. The esophagus (B) is a part of the digestive tract but not an accessory organ. The stomach (C) and small intestine (D) are primary organs of digestion, not accessory organs.

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: digestive enzymes. The pancreas secretes digestive enzymes such as amylase, lipase, and protease to break down carbohydrates, fats, and proteins in the small intestine. Insulin (choice A) is a hormone that regulates blood sugar levels, not aid in digestion. Gastric acid (choice B) is produced by the stomach, not the pancreas. Bile (choice D) is produced by the liver and stored in the gallbladder to aid in fat digestion, not directly secreted by the pancreas for digestion.

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.