Which organ produces bile?

Correct Answer: C

Rationale: The correct answer is C: Liver. The liver produces bile, which plays a crucial role in digestion by breaking down fats. The pancreas (A) produces digestive enzymes, not bile. The gallbladder (B) stores bile produced by the liver but does not produce it. The stomach (D) produces gastric juices, not bile. Therefore, the liver is the only organ that produces bile, making it the correct answer.

Correct Answer: C

Rationale: The correct answer is C: CCK. Cholecystokinin (CCK) is a hormone released by the small intestine in response to the presence of fatty acids and amino acids. It stimulates the release of bile from the gallbladder and increases bile production by the liver cells to aid in digestion. Sympathetic activation (choice A) typically inhibits digestive functions. Secretin (choice B) primarily stimulates pancreatic bicarbonate secretion, not bile production. Bile salts (choice D) are products of bile, not direct stimulators of bile production. Therefore, CCK is the correct choice as it directly influences the production of bile by the liver cells.

Correct Answer: D

Rationale: The correct answer is D: Mainly found in the colon. Intestinal flora, also known as gut microbiota, is primarily located in the colon. This is because the colon provides an ideal environment for the growth and survival of the diverse array of beneficial bacteria that make up the intestinal flora. These bacteria play a crucial role in various physiological functions, such as digestion, immune system regulation, and vitamin production. Choices A, B, and C are incorrect because intestinal flora are predominantly bacteria (not viruses), are not solely located in the duodenum but throughout the gastrointestinal tract, and are essential for normal digestion, not just needed.

Correct Answer: A

Rationale: Saliva contains an enzyme called amylase, which helps break down sucrose (a type of sugar) into glucose and fructose for digestion. Therefore, the correct answer is A. Saliva does not play a significant role in the digestion of phospholipids (B), speaking ability (C), or breaking food down into small pieces (D).

Correct Answer: B

Rationale: The correct answer is B because the small intestine has a larger internal surface area compared to the large intestine due to its extensive folding and villi. This increased surface area enhances nutrient absorption efficiency. Choice A is incorrect as the small intestine is longer than the large intestine. Choice C is incorrect as the small intestine absorbs more water than the large intestine. Choice D is incorrect as the small intestine typically does not contain the same amount of bacteria as the large intestine, which is known for its significant bacterial population.