The following hormones are important to the normal function of the gut: ( Select one that does not apply)

Correct Answer: C

Rationale: The correct answer is C: Hydrogen potassium ATPase. This enzyme is not a hormone involved in the normal function of the gut. Gastrin, Secretin, and Cholecystokinin-pancreozymin (CCK-PZ) are all hormones that play important roles in regulating digestion and gut functions. Gastrin stimulates gastric acid secretion, Secretin regulates pancreatic and bile secretions, and CCK-PZ stimulates pancreatic enzyme secretion and gallbladder contraction. Therefore, C is the correct answer because Hydrogen potassium ATPase is not a hormone relevant to gut function.

Correct Answer: A

Rationale: The correct answer is A: The gullet. Food passes through the gullet, also known as the esophagus, between the mouth and the stomach. The gullet is a muscular tube that contracts to push the food down to the stomach for digestion. The other choices are incorrect because the rectum is where waste is stored before elimination, the small intestine is where most of the absorption of nutrients occurs, and the large intestine is where water is absorbed and waste is further processed before excretion.

Correct Answer: A

Rationale: The correct answer is A because the function of structure X's secretions is to increase the surface area of fats for better digestion and absorption in the small intestine. This is achieved by emulsifying fats into smaller droplets, aiding in their breakdown by lipase enzymes. Choices B, C, and D are incorrect as structure X is not involved in stomach acid secretion to decrease pH, protein digestion to peptides, or glycogen breakdown to maltose. The primary role of structure X is related to fat digestion, making choice A the most suitable option.

Correct Answer: A

Rationale: The correct answer is A: basic. Trypsin is a protease enzyme that functions best in basic conditions, specifically at a pH around 8. This is because its active site contains amino acid residues that are positively charged at basic pH, facilitating substrate binding and catalysis. In acidic conditions (choice B), the active site residues may become protonated and lose their positive charge, leading to decreased enzyme activity. Neutral conditions (choice C) are suboptimal for trypsin as it requires basic pH for optimal function. Low pH (choice D) is also not ideal for trypsin as it can denature the enzyme and hinder its catalytic activity.

Correct Answer: C

Rationale: The correct answer is C: liver. Glycogen is primarily stored in the liver and muscles. The liver serves as a major storage site for glycogen, acting as a reservoir for glucose when blood sugar levels drop. The pancreas (A) mainly produces digestive enzymes and hormones like insulin and glucagon. The small intestine (B) is involved in nutrient absorption, not glycogen storage. The large intestine (D) is mainly responsible for absorbing water and electrolytes, not storing glycogen. Therefore, C is the correct answer.