Nokea
The release of gastric secretions is stimulated by nerve and hormonal stimuli and the:
- A. ingestion of water.
- B. swallowing reflex.
- C. presence of food in the stomach.
- D. closing of the pyloric sphincter.
Correct Answer: C
Rationale: The correct answer is C: 'presence of food in the stomach.' Gastric secretions are stimulated when food enters the stomach, triggering nerve and hormonal responses. This process prepares the stomach for digestion. Choices A, B, and D are incorrect because ingesting water, swallowing reflex, and the closing of the pyloric sphincter do not directly stimulate the release of gastric secretions.
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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.
What is the cause of gas formation in the colon?
- A. Consuming refined foods.
- B. Drinking excess water.
- C. Swallowing air while eating.
- D. Bacterial action on organic compounds.
Correct Answer: D
Rationale: Gas formation in the colon is primarily due to bacterial fermentation of undigested carbohydrates. Choice A, consuming refined foods, is incorrect as gas formation is not directly linked to refined foods but rather undigested carbohydrates. Choice B, drinking excess water, is incorrect as water consumption does not lead to gas formation in the colon. Choice C, swallowing air while eating, is incorrect as this may cause belching but not gas formation in the colon. The correct answer is D because bacterial action on organic compounds, specifically undigested carbohydrates, leads to gas production in the colon.
At what pH does the digestion of protein by pepsin in the stomach require?
- A. 1.8 and 3.5.
- B. 4.8 and 7.0.
- C. 6.8 and 8.5.
- D. 7.8 and 10.0.
Correct Answer: A
Rationale: The correct answer is A: 1.8 and 3.5. Pepsin, an enzyme involved in protein digestion, functions optimally in an acidic environment, specifically between pH 1.8 and 3.5. This low pH is necessary for pepsin to break down proteins effectively. Choices B, C, and D are incorrect because pepsin requires a highly acidic environment, ruling out the pH ranges listed in those options.
What are probiotics?
- A. Indigestible carbohydrates that promote growth of health-promoting bacteria.
- B. Antibiotics that prevent growth of harmful bacteria.
- C. Nutritional supplements of health-promoting bacteria.
- D. Commercial fiber supplements that have a laxative effect.
Correct Answer: C
Rationale: Probiotics are live bacteria that are beneficial for gut health and are often taken as supplements. They are not indigestible carbohydrates (Choice A), antibiotics (Choice B), or commercial fiber supplements (Choice D). Probiotics contain live strains of good bacteria that help maintain a healthy balance in the gut microbiome.