Which is NOT part of the normal content of gastric juice?

Correct Answer: D

Rationale: The correct answer is D: amylase. Gastric juice primarily consists of hydrochloric acid, pepsin, and mucus. Amylase is an enzyme produced in the pancreas, not in the stomach. It functions in the small intestine to break down carbohydrates. Therefore, amylase is not a normal component of gastric juice. Choices A, B, and C are incorrect because HPO42- (phosphate ions), mucus, and lipase are all typically found in gastric juice.

Correct Answer: B

Rationale: The correct answer is B because men lose about 0.6mg of iron per day through various physiological processes like shedding skin cells and hair. This loss must be replenished through dietary intake to maintain iron balance. Choice A is incorrect as iron is more readily absorbed in the ferrous form. Choice C is incorrect as the average daily iron intake is around 18mg. Choice D is incorrect ascorbic acid enhances iron absorption rather than reducing it.

Correct Answer: D

Rationale: The correct answer is D: Thyroid. The thyroid gland produces hormones T3 and T4, which regulate the body's metabolism, including the basal metabolic rate (BMR). These hormones play a crucial role in controlling how the body uses energy. The other choices, A: Parathyroid, B: Pancreas, and C: Testes, do not directly regulate BMR. Parathyroid regulates calcium levels, pancreas regulates blood sugar levels, and testes produce hormones related to male reproductive functions. Thyroid is the only gland among the choices that specifically controls BMR through its hormone production.

Correct Answer: C

Rationale: The correct answer is C: Mouth. Ingestion is the process of taking food or liquid into the body through the mouth. The mouth is responsible for chewing and breaking down food into smaller pieces, mixing it with saliva to start the digestion process. The stomach (A), small intestine (B), and large intestine (D) are not where ingestion takes place; they are involved in further digestion, absorption, and processing of nutrients. The mouth is the initial site of digestion and the starting point of the digestive process.

Correct Answer: A

Rationale: The correct answer is A: The pyloric sphincter. This is because the pyloric sphincter is the muscular valve located at the lower end of the stomach that controls the flow of partially digested food (chyme) into the small intestine. It regulates the release of food from the stomach into the duodenum for further digestion and absorption. Summary of incorrect choices: B: The ilea caecal valve - This valve is located between the ileum (part of the small intestine) and the cecum (part of the large intestine), not the stomach. C: The pelvic sphincter - This sphincter is associated with the rectum and anus, not the stomach. D: The pylorus sphincter - Similar to the correct answer, but the correct term is pyloric sphincter.