What does the term 'chyme' refer to?

Correct Answer: C

Rationale: The term 'chyme' refers to food mixed with digestive juices in the stomach. This mixture is the result of mechanical and chemical digestion processes. Choice A, undigested food, is incorrect as chyme is a product of digestion. Choice B, partially digested food, is not precise enough as chyme specifically refers to the semi-fluid mass in the stomach. Choice D, absorbed nutrients, is incorrect as chyme is not yet at the stage where nutrients are absorbed. Thus, choice C is correct as it accurately describes the composition of chyme in the digestive system.

Correct Answer: B

Rationale: The correct answer is B: Liver. The liver is an accessory digestive organ as it produces bile, which aids in the digestion and absorption of fats in the small intestine. The other choices, A: Esophagus, C: Stomach, and D: Small intestine, are primary digestive organs involved directly in the process of digestion and absorption of nutrients. The esophagus is responsible for transporting food to the stomach, the stomach digests food with gastric juices, and the small intestine is where most of the digestion and absorption of nutrients occur. Therefore, the liver stands out as the correct answer as it supports the digestive process rather than directly participating in it.

Correct Answer: B

Rationale: The correct answer is B: Common bile duct. Gas is not typically present in the common bile duct in a normal healthy individual. The presence of gas in the stomach (A), small intestine (C), and transverse colon (D) is expected due to normal digestive processes. Gas in the common bile duct could indicate an abnormality such as a blockage or infection. Therefore, the absence of gas in the common bile duct on an X-ray of a normal healthy man is expected.

Correct Answer: C

Rationale: The correct answer is C: Lactose. Brush border enzymes in the small intestine, specifically lactase, digest lactose into its component sugars, glucose, and galactose. Lactose is a disaccharide found in dairy products that needs to be broken down for absorption. Starch (A) is primarily digested by salivary and pancreatic amylase. Cholesterol esters (B) are broken down by pancreatic enzymes. Galactose (D) is a monosaccharide that is a product of lactose digestion, not directly digested by brush border enzymes.

Correct Answer: A

Rationale: The correct answer is A: pyloric stenosis. This condition typically presents at 2-4 weeks of age and is more common in males. The rationale behind this is that pyloric stenosis is the narrowing of the passage between the stomach and small intestine, leading to projectile vomiting after feeding, which becomes apparent around 2-4 weeks of age. Intestinal atresia, Meckel's diverticulum, and Hirschsprung's disease do not typically present with symptoms at this specific age range and do not have a strong male preponderance as seen in pyloric stenosis.