Which of the following structures would be considered retroperitoneal?

Correct Answer: A

Rationale: The correct answer is A: pancreas. The pancreas is considered retroperitoneal because it lies behind the peritoneum, specifically in front of the vertebral column. This positioning makes it retroperitoneal, unlike the stomach, jejunum, and spleen, which are intraperitoneal organs located within the peritoneal cavity. The retroperitoneal location of the pancreas helps protect it and provides structural support. It also allows for easier access during surgical procedures, as it is not surrounded by peritoneum on all sides like intraperitoneal organs.

Correct Answer: C

Rationale: Histamine stimulates the parietal cells in the stomach lining to release hydrochloric acid (HCl). This process plays a crucial role in the digestion of food. Parietal cells are responsible for producing stomach acid, which helps break down food and kill bacteria. Choice A is incorrect because intrinsic factor is not released by parietal cells in response to histamine. Choice B is incorrect because pepsinogen is released by chief cells, not parietal cells. Choice D is incorrect because mucous neck cells secrete mucus to protect the stomach lining, but they are not directly stimulated by histamine to release mucus.

Correct Answer: D

Rationale: The correct answer is D: cirrhosis. Jaundice, pale skin, and liver with connective tissue buildup are classic symptoms of cirrhosis - a condition characterized by scarring of the liver due to long-term damage. Jaundice occurs when the liver is unable to properly process bilirubin, leading to yellowing of the skin and eyes. The pale color can be due to anemia often seen in cirrhosis. The buildup of connective tissue is indicative of fibrosis and scarring in the liver. Gastritis (A) is inflammation of the stomach lining, pancreatitis (B) is inflammation of the pancreas, and gallstones (C) are solid particles that form in the gallbladder. These conditions do not typically present with the combination of symptoms described.

Correct Answer: A

Rationale: The correct answer is A: mass movements. Mass movements are strong contractions that occur 3 to 4 times a day, moving large amounts of fecal material through the colon. This process involves the transverse and descending colon, which aligns with the description provided in the question. Mass movements help propel waste towards the rectum for elimination. Choice B, haustral churning, refers to the mixing and propelling actions that occur in the haustra of the colon, not involving large parts of the transverse and descending colon. Choice C, the defecation reflex, is the process that triggers the urge to defecate, not specific contractions involving the colon. Choice D, teniae coli waves, are contractions of the longitudinal muscles of the colon that create the haustra, not the strong propulsive contractions described in the question.

Correct Answer: D

Rationale: Rationale for Correct Answer D (Triglycerides must be emulsified and digested before fatty acids can be transported): 1. Triglycerides are large molecules that cannot be directly absorbed by the intestinal cells. 2. Emulsification breaks down triglycerides into smaller droplets, increasing the surface area for enzyme action. 3. Enzymatic digestion of triglycerides by lipases results in the release of fatty acids and monoglycerides. 4. These breakdown products are then absorbed by enterocytes in the small intestine. Summary of Why Other Choices are Incorrect: A: FABP and FAT/CD36 proteins are involved in fatty acid transport, not triglyceride digestion. B: Both medium and long-chain triglycerides are absorbed into the lymphatic system via chylomicrons. C: While mixed micelles aid in lipid absorption, they are not essential for the initial digestion of triglycerides.