Nokea
The cells of the epithelial lining in the vertebrate stomach are not damaged by HCl because of
- A. Mucus secretion covering the epithelium
- B. Neutralization of HCl by alkaline gastric juice
- C. HCl being dilute
- D. Epithelium being resistant to HCl
Correct Answer: A
Rationale: Mucus secreted by gastric cells forms a protective barrier against HCl, preventing damage to the stomach lining.
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Carcinoid tumor, Is tumor of:
- A. Parietal cells
- B. Enteroendocrine APUD cells
- C. Zymogen cell
- D. Paneth cells
Correct Answer: B
Rationale: Carcinoid tumors arise from enteroendocrine (APUD) cells, which secrete hormones like serotonin.
Match: Disaccharide
- A. a sugar composed of two monosaccharides
- B. stored form of energy
- C. used in DNA synthesis
- D. component of cell membranes
Correct Answer: A
Rationale: Disaccharides, like sucrose, consist of two monosaccharides linked together and are broken down into simpler sugars during digestion.
Secretin is a hormone that:
- A. stimulates the release of pancreatic fluid
- B. converts trypsinogen into trypsin
- C. activates chymotrypsin
- D. inhibits the action of pancreatic lipase
Correct Answer: A
Rationale: Secretin stimulates the pancreas to release bicarbonate-rich fluids to neutralize stomach acid.
Which of the following would MOST directly affect the operations of the digestive system?
- A. osteoporosis
- B. liver damage
- C. heart attack
- D. kidney failure
Correct Answer: B
Rationale: Liver damage directly impacts digestion by reducing bile production, essential for fat breakdown.
All of the following are components of saliva EXCEPT?
- A. Mucin
- B. Pepsin
- C. Amylase
- D. IgA antibodies
Correct Answer: B
Rationale: Pepsin is not a component of saliva; it is found in the stomach where it helps digest proteins. Saliva contains mucin, amylase, and IgA antibodies.