Contraction of the gallbladder may be due to:

Correct Answer: C

Rationale: The correct answer is C: Bile salts. Bile salts play a crucial role in the contraction of the gallbladder. When bile salts are released into the duodenum, they stimulate the gallbladder to contract, releasing bile into the small intestine to aid in digestion. Secretin (choice A) and VIP (choice B) are hormones that primarily regulate pancreatic secretion, not gallbladder contraction. Atropine (choice D) is an anticholinergic drug that inhibits the parasympathetic nervous system and would not stimulate gallbladder contraction. Therefore, the correct answer is C as bile salts directly trigger the contraction of the gallbladder.

Correct Answer: C

Rationale: The correct answer is C: peptic ulcer. Peptic ulcers are a common cause of upper gastrointestinal hemorrhage due to erosion of the stomach lining. The acidic environment in the stomach can lead to ulcer formation. Esophageal varices are associated with liver cirrhosis, not a common cause of hemorrhage. Gastric carcinoma may cause bleeding but is less common than peptic ulcers. Gastritis is inflammation of the stomach lining and can cause bleeding but is not as common as peptic ulcers.

Correct Answer: C

Rationale: The correct answer is C: Saliva contains alpha amylase. Saliva does indeed contain the enzyme alpha amylase, which helps in the breakdown of carbohydrates in the mouth. This is a well-established fact in human physiology. Explanation for why other choices are incorrect: A: HCL converts pepsin into pepsinogen - This statement is incorrect as pepsinogen is converted into pepsin by the acidic environment in the stomach, not the other way around. B: IF is essential for vitamin K absorption - This is also incorrect. Intrinsic factor (IF) is essential for the absorption of vitamin B12, not vitamin K. D: Myenteric plexus controls GIT secretion - While the myenteric plexus is involved in regulating gastrointestinal motility, it is not primarily responsible for controlling secretion in the gastrointestinal tract.

Correct Answer: B

Rationale: Step 1: HCL helps in the digestion of food by creating an acidic environment in the stomach. Step 2: This acidic environment aids in the breakdown of food components, including iron. Step 3: Iron absorption is enhanced in the presence of HCL. Conclusion: Choice B is correct as HCL helps in the absorption of iron. Choices A, C, and D are incorrect as HCL does not inhibit pepsinogen, aid in absorption of vitamin B12, or secreted in response to sympathetic stimulation.

Correct Answer: B

Rationale: The correct answer is B: Rugae, Increase. Rugae are folds in the mucosa of the stomach that allow for expansion of the stomach when food is ingested, increasing the surface area for digestion and absorption. Rugae help in mixing and breaking down food efficiently. Explanation: 1. Rugae are specifically found in the stomach to increase surface area for digestion. 2. The folds of rugae help in stretching the stomach to accommodate food intake. 3. Increased surface area aids in better absorption of nutrients. 4. Crypts are invaginations in the mucosa but not related to increasing surface area. 5. Option C and D are incorrect because rugae actually increase, not decrease, the surface area of the stomach.