Which of the following symptoms of diabetes mellitus is correctly matched to its description?

Correct Answer: D

Rationale: The correct answer is D, glycosuria - excessive sugar in the urine. In diabetes mellitus, high blood sugar levels lead to glucose spilling into the urine, causing glycosuria. Polyuria (excessive urine) is due to the kidneys trying to eliminate the excess glucose. Polyphagia (excessive hunger) results from cells not receiving enough glucose for energy. Polydipsia (excessive thirst) occurs as a result of dehydration from polyuria. Choice D is correct as it directly relates to the presence of sugar in the urine, a hallmark symptom of diabetes mellitus.

Correct Answer: B

Rationale: The correct answer is B: Pineal gland. The pineal gland secretes melatonin, a hormone that regulates the body's sleep-wake cycle, thus contributing to setting the body's biological clock. This gland responds to light and darkness, helping to synchronize our internal clock with the day-night cycle. The pituitary gland (A) regulates various hormones but not specifically the biological clock. The thymus gland (C) is responsible for immune function, not the biological clock. The adrenal gland (D) secretes hormones related to stress response, not the biological clock. In summary, the pineal gland is key in regulating the body's biological clock through melatonin secretion, making it the correct choice.

Correct Answer: B

Rationale: The correct answer is B because a congenital defect in gastric lipase would not lead to steatorrhoea. Gastrinoma, ileal disease with failure to reabsorb bile salts, and exocrine pancreatic disease can all cause steatorrhoea due to impaired fat digestion or absorption. Gastrinoma can lead to excessive acid production, which can interfere with fat digestion. Ileal disease can affect the reabsorption of bile salts necessary for fat digestion. Exocrine pancreatic disease can result in insufficient pancreatic enzymes needed for fat digestion. Therefore, choice B is the exception as it does not directly impact fat digestion or absorption.

Correct Answer: C

Rationale: Rationale for Correct Answer C: Oligosaccharidase deficiency leads to osmotic diarrhea because the incomplete breakdown of oligosaccharides in the small intestine results in unabsorbed sugars attracting water, causing diarrhea. This is a direct consequence of the deficiency in enzymes responsible for breaking down oligosaccharides. This is why Choice C is correct. Summary of Incorrect Choices: A: Salivary amylase works best at a neutral pH of around 6.7, not alkaline pH. B: Lactose intolerance is due to a deficiency in lactase enzyme, not related to carbohydrate digestion in the small intestine. D: Salivary amylase is inactivated in the acidic environment of the stomach, so it does not continue to digest carbohydrates there.

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.