Where are most fats digested?

Correct Answer: C

Rationale: The correct answer is C: small intestine. Fats are primarily digested in the small intestine. First, bile from the liver emulsifies fats, breaking them down into smaller droplets. Then, pancreatic enzymes like lipase break down these smaller droplets into fatty acids and glycerol for absorption. The small intestine is where the majority of nutrient absorption occurs, making it the main site for fat digestion. Explanation of why other choices are incorrect: A: Stomach - Minimal fat digestion occurs in the stomach as it primarily focuses on protein digestion. B: Pancreas - The pancreas secretes enzymes that aid in fat digestion, but the actual breakdown of fats happens in the small intestine. D: Large intestine - Fat digestion is not a primary function of the large intestine; it mainly absorbs water and electrolytes.

Correct Answer: B

Rationale: The correct answer is B: Total gastrectomy. This operation involves complete removal of the stomach, leading to the inability to digest food. Without a stomach, essential nutrients cannot be absorbed, necessitating parenteral feeding. A: Total oesophagectomy - Although the esophagus is important for swallowing, parenteral feeding can sustain life without it. C: Right hepatic lobectomy - The liver has regenerative capacity and can compensate for the loss of a lobe. D: Total oroclocolectomy - This operation removes the entire colon, but parenteral feeding can still provide nutrition. In summary, total gastrectomy results in the loss of the major organ responsible for digestion and nutrient absorption, requiring parenteral feeding for survival.

Correct Answer: D

Rationale: The correct answer is D: Intrinsic factor. Saliva does not normally contain intrinsic factor, which is a protein produced by the stomach to aid in the absorption of vitamin B12. Saliva does contain isozymes, IgA antibodies, and lactoferrin. Isozymes are different forms of enzymes, IgA is an antibody important for immune defense, and lactoferrin is a protein with antimicrobial properties found in saliva. Therefore, D is the correct answer as intrinsic factor is not a normal component of saliva.

Correct Answer: B

Rationale: The correct answer is B: Hirschsprung's disease. The absence of ganglion cells in the distal colon is a key diagnostic feature of Hirschsprung's disease. Ganglion cells are essential for coordinated contractions of the colon. In congenital pyloric stenosis, the issue lies in the pylorus, not the colon, so ganglion cells are not relevant. Choice C is incorrect because congenital pyloric stenosis does not involve ganglion cells. Choice D is also incorrect as Hirschsprung's disease does indeed involve the absence of ganglion cells.

Correct Answer: C

Rationale: The correct answer is C because carcinoma of the esophagus often spreads locally, making complete removal difficult. This local spread can involve nearby structures, leading to a poor prognosis. Metastases to the liver or lung (choice A) typically occur later in the disease course, not before diagnosis. While some esophageal tumors may be challenging to access surgically (choice B), this alone does not explain the poor prognosis. Esophageal cancer can respond to radiotherapy (choice D), so radioresistance is not the primary reason for the poor prognosis. In summary, the local spread preventing complete removal is the key factor contributing to the poor prognosis in esophageal carcinoma.