What does the pancreas secrete to aid digestion?

Correct Answer: C

Rationale: The correct answer is C: digestive enzymes. The pancreas secretes digestive enzymes such as amylase, lipase, and protease to aid in the digestion of carbohydrates, fats, and proteins in the small intestine. These enzymes break down food molecules into smaller nutrients that can be absorbed by the body. Bile (choice A) is produced by the liver and stored in the gallbladder, not the pancreas. Gastric acid (choice B) is produced by the stomach to aid in the digestion of proteins. Insulin (choice D) is a hormone produced by the pancreas that regulates blood sugar levels, not aid in digestion.

Correct Answer: D

Rationale: The correct answer is D: Contraction of pancreatic acini. Cholecystokinin (CCK) is a hormone that is released in response to the presence of food in the small intestine. It stimulates the contraction of the smooth muscle in the walls of the pancreatic acini, leading to the release of digestive enzymes into the small intestine to aid in digestion. This action is crucial for the proper breakdown of food molecules. Options A, B, and C are incorrect because CCK does not have a direct effect on oesophageal motility, the sphincter of Oddi, or bile synthesis.

Correct Answer: D

Rationale: The correct answer is D because micelles are indeed clusters of cholesterol, fatty acids, bile salts, and 2 mono-glycerides formed in the small intestine during lipid digestion. This process aids in the absorption of lipids by increasing their surface area for enzymatic action. Choice A is incorrect as emulsified fat globules are not micelles, but rather the initial step in lipid digestion. Choice B is incorrect as pro-enzymes are not related to micelles. Choice C is incorrect as dead enterocytes are not involved in micelle formation.

Correct Answer: D

Rationale: The correct answer is D because iron absorption is regulated to meet the body's needs. When body stores are low or erythropoiesis is increased, absorption increases. This process occurs mainly in the duodenum and upper jejunum, not the terminal ileum as stated in option C. Option A is incorrect because HCl aids in converting iron into a more absorbable form but does not determine the percentage absorbed. Option B is incorrect as the majority of iron absorption occurs in the duodenum and upper jejunum, not the small intestine in general.

Correct Answer: A

Rationale: The correct answer is A: resecting the constricted segment. In Hirschsprung's disease, there is a lack of ganglion cells in the distal bowel causing a functional obstruction. The treatment involves surgically removing the affected segment to allow normal bowel function. Resecting the dilated segment (choice B) is not effective as the issue lies in the constricted area. Colectomy and ileostomy (choice C) is an extreme measure and is usually reserved for severe cases. Avoiding surgical intervention (choice D) is not recommended as it can lead to complications and worsen the condition.