Cholecystokinin (CCK) is produced in the:
- A. duodenum.
- B. stomach.
- C. pancreas.
- D. liver.
Correct Answer: A
Rationale: Cholecystokinin (CCK) is produced in the duodenum, not the stomach, pancreas, or liver. It is released in response to the presence of food in the duodenum, where it plays a crucial role in regulating digestive processes by stimulating the release of bile from the gallbladder and enzymes from the pancreas. Therefore, the correct answer is the duodenum (Choice A). Choices B, C, and D are incorrect because CCK is not produced in the stomach, pancreas, or liver.
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Which hormone prevents excessive gastric activity?
- A. Gastrin
- B. Enterogastrone
- C. Secretin
- D. Cholecystokinin
Correct Answer: B
Rationale: The correct answer is Enterogastrone. Enterogastrone is a hormone that inhibits excessive gastric activity by slowing down stomach contractions and emptying. Gastrin (choice A) stimulates gastric acid secretion, secretin (choice C) regulates pH levels in the duodenum, and cholecystokinin (choice D) stimulates the release of digestive enzymes and bile.
After absorption, the end products of carbohydrate and protein digestion enter the:
- A. enterohepatic circulation.
- B. gastrointestinal circulation.
- C. common bile duct.
- D. portal blood system.
Correct Answer: D
Rationale: The correct answer is D: portal blood system. After absorption, carbohydrates and proteins are transported via the portal blood system to the liver for further processing and distribution to the rest of the body. Choices A, B, and C are incorrect. Enterohepatic circulation refers to the recycling of compounds between the liver and the intestines, not the direct route for absorbed nutrients. Gastrointestinal circulation is a vague and non-specific term, not specifically related to the transport of absorbed nutrients. The common bile duct is involved in transporting bile from the liver and gallbladder to the small intestine, not the end products of carbohydrate and protein digestion.
After ingested food is mixed and churned with gastric secretions, the resulting semifluid mass is called:
- A. a bolus.
- B. chyme.
- C. rennin.
- D. glycogen.
Correct Answer: B
Rationale: The correct answer is B: chyme. Chyme is the partially digested food that forms a semifluid mass after mixing with gastric juices. A is incorrect because a bolus refers to a rounded mass of food ready to be swallowed. C, rennin, is an enzyme involved in the digestion of milk proteins and not the term for the semifluid mass after food mixing with gastric secretions. D, glycogen, is a form of stored glucose in the body and is not the term used to describe the partially digested food mass in the stomach.
What are the small, fingerlike projections into the intestinal lumen called?
- A. Villi
- B. Goblets
- C. Lacteals
- D. Polyps
Correct Answer: A
Rationale: The correct answer is A: Villi. Villi are small fingerlike projections in the intestine that increase the surface area for nutrient absorption. Goblets (choice B) are mucus-secreting cells in the intestines. Lacteals (choice C) are lymphatic vessels in the small intestine that absorb dietary fats. Polyps (choice D) are abnormal tissue growths.
What substance acts as an emulsifier and helps absorb digested fat?
- A. bile
- B. trypsin
- C. lipase
- D. cholecystokinin (CCK)
Correct Answer: A
Rationale: The correct answer is A: bile. Bile acts as an emulsifier, breaking down fats into smaller droplets to aid in digestion and absorption. Trypsin is a digestive enzyme that acts on proteins, not fats. Lipase is an enzyme that breaks down fats, but it doesn't act as an emulsifier. Cholecystokinin (CCK) is a hormone that stimulates the release of digestive enzymes, including lipase, but it is not directly involved in emulsification.