Nokea
In addition to active transport, which process is involved in absorbing food in the small intestine?
- A. pinocytosis
- B. excretion
- C. phagocytosis
- D. electrochemical diffusion
Correct Answer: A
Rationale: The correct answer is pinocytosis. Pinocytosis is a process where cells in the small intestine absorb nutrients by engulfing them. This process is different from phagocytosis, which involves engulfing large particles, and excretion, which is the removal of waste products. Electrochemical diffusion is not directly involved in the absorption of food in the small intestine.
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Which hormone stimulates the gallbladder to contract?
- A. Secretin.
- B. Cholecystokinin (CCK).
- C. Gastrin.
- D. Gastric inhibitory polypeptide (GIP).
Correct Answer: B
Rationale: Cholecystokinin (CCK) is the hormone responsible for stimulating the gallbladder to contract and release bile into the small intestine. Secretin primarily acts on the pancreas to stimulate the secretion of bicarbonate-rich fluid. Gastrin functions in the stimulation of gastric acid secretion, while Gastric inhibitory polypeptide (GIP) plays a role in inhibiting gastric acid secretion and stimulating insulin release.
The rate of gastric emptying depends on the:
- A. time of day food is consumed.
- B. composition of food consumed.
- C. rate of food consumption.
- D. frequency of eating.
Correct Answer: B
Rationale: The rate at which the stomach empties its contents is primarily determined by the composition of the food consumed. Foods high in fat and protein tend to slow down gastric emptying, while foods high in carbohydrates usually pass through more quickly. Therefore, the composition of food consumed directly impacts the rate of gastric emptying. Choices A, C, and D are incorrect as they do not directly affect the rate of gastric emptying.
The lining of the stomach and intestine is protected from self-digestion by:
- A. pepsinogen.
- B. bile.
- C. mucus.
- D. fat.
Correct Answer: C
Rationale: The correct answer is C: mucus. Mucus forms a protective barrier that prevents the stomach and intestine from digesting themselves. Pepsinogen (choice A) is an inactive form of pepsin, a digestive enzyme, and does not protect the stomach lining. Bile (choice B) aids in the digestion and absorption of fats but does not protect the stomach lining. Fat (choice D) is a nutrient and energy source; it does not play a role in protecting the stomach and intestine from self-digestion.
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 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.