Cells in duodenum monitor chyme coming from the stomach that has a pH of 1. You would expect the duodenal cells to

Correct Answer: C

Rationale: The correct answer is C because duodenal cells release secretin in response to low pH in chyme. Secretin inhibits gastric secretions by stimulating the pancreas to release bicarbonate-rich fluid to neutralize the acidic chyme. Option A is incorrect because gastric inhibitory polypeptide and cholecystokinin actually stimulate pancreatic secretion, not inhibit gastric secretions. Option B is incorrect as the enterogastric reflex decreases gastric secretions to slow down the rate of emptying the stomach, not increase it. Option D is incorrect because enterogastrone is a hypothetical hormone and not involved in the regulation of gastric secretions.

Correct Answer: D

Rationale: The correct answer is D: amylase. Amylase is the enzyme responsible for breaking down starch into maltose. It works by catalyzing the hydrolysis of the glycosidic bonds between glucose molecules in starch. Lipase (A) breaks down lipids, not carbohydrates. Maltase (B) is responsible for breaking down maltose into glucose. Lactase (C) breaks down lactose, not starch. Therefore, amylase is the correct enzyme for breaking down starch into maltose.

Correct Answer: C

Rationale: The correct answer is C because hemicelluloses, pectins, and inulin are indeed rapidly fermented to short-chain fatty acids in the colon, providing trophic effects. This is supported by scientific evidence. Choice A is incorrect because the main end products of fermentation of dietary fiber are short-chain fatty acids, not malic, succinic, and propionic acids. Choice B is incorrect as not all forms of fiber are completely fermented within 24 hours, and the time frame can vary. Choice D is incorrect because stool bulking is primarily attributed to soluble fibers, which hold water and increase stool bulk, rather than insoluble fibers like cellulose.

Correct Answer: D

Rationale: The correct answer is D (P, Q, R, and S). P is correct because mechanical digestion does occur in the stomach through the churning action of the stomach muscles. Q is correct as cholecystokinin, gastrin, and secretin are indeed produced by enteroendocrine cells in the gastrointestinal tract. R is correct because the pancreas, small intestine, and salivary glands produce digestive enzymes to aid in the breakdown of food. S is correct as mucous neck cells, chief cells, and parietal cells are all present in the stomach and play roles in the digestion process. Therefore, all options P, Q, R, and S are correct, making answer choice D the correct one.

Correct Answer: A

Rationale: Rationale: Creatine primarily benefits high-intensity, short-duration activities by aiding in quick energy production through ATP regeneration. All-out sprints fall under this category, making creatine supplementation effective. In contrast, choices B and C involve longer durations where creatine's benefits are less pronounced. Choice D is incorrect as creatine has been shown to enhance performance in specific exercise scenarios.