Which of the following cells produce hydrochloric acid?

Correct Answer: A

Rationale: The correct answer is A: parietal cells. Parietal cells are located in the gastric glands of the stomach and are responsible for producing hydrochloric acid to help with digestion. They also secrete intrinsic factor, which is essential for vitamin B12 absorption. Enteroendocrine cells (B) produce hormones, mucous neck cells (C) secrete mucus to protect the stomach lining, and chief cells (D) produce pepsinogen for protein digestion, but they do not produce hydrochloric acid. Therefore, parietal cells are the only cells among the choices that specifically produce hydrochloric acid.

Correct Answer: A

Rationale: The correct answer is A: Amylase. Amylase is responsible for the digestion of carbohydrates by breaking down starches into simple sugars like glucose. It is produced in the salivary glands and pancreas, and works in both the mouth and small intestine. Lipase (B) digests fats, Pepsin (C) digests proteins, and Trypsin (D) also digests proteins but not carbohydrates. Therefore, they are not responsible for the digestion of carbohydrates.

Correct Answer: D

Rationale: The correct answer is D: Enteropeptidase. Enteropeptidase is not produced by the exocrine pancreas; it is produced by the duodenal mucosa. Proelastase, DNase, and amylase are enzymes produced by the exocrine pancreas. Proelastase is involved in the breakdown of elastin, DNase breaks down DNA, and amylase helps in the digestion of carbohydrates. Therefore, the correct answer is D because Enteropeptidase is not produced by the exocrine pancreas but by the duodenal mucosa.

Correct Answer: C

Rationale: The correct answer is C: Bile salts. Bile salts play a crucial role in the contraction of the gallbladder. When bile salts are released into the duodenum, they stimulate the gallbladder to contract, releasing bile into the small intestine to aid in digestion. Secretin (choice A) and VIP (choice B) are hormones that primarily regulate pancreatic secretion, not gallbladder contraction. Atropine (choice D) is an anticholinergic drug that inhibits the parasympathetic nervous system and would not stimulate gallbladder contraction. Therefore, the correct answer is C as bile salts directly trigger the contraction of the gallbladder.

Correct Answer: D

Rationale: The correct answer is D: Bile salts. Bile salts are primarily absorbed in the terminal ileum, not in the duodenum or jejunum. The duodenum and jejunum are mainly responsible for absorbing nutrients like glucose, fat-soluble vitamins, and vitamin C. Bile salts aid in the digestion and absorption of fats, but they are reabsorbed in the ileum to be recycled. Therefore, the duodenum and jejunum are not the main sites for the absorption of bile salts.