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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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.
Amylase enzyme acts on which substrate ______________.
- A. Protein.
- B. Carbohydrates.
- C. Fatty acids.
- D. Fat.
Correct Answer: B
Rationale: Amylase is an enzyme that breaks down carbohydrates into simpler sugars like maltose and dextrin.
Of the following, which organ does food NOT pass through?
- A. pancreas
- B. stomach
- C. mouth
- D. small intestine
Correct Answer: A
Rationale: Food does not pass through the pancreas; it produces digestive enzymes that aid digestion.
All enzymes involved in protein digestion are:
- A. secreted by the pancreas
- B. activated by HCl
- C. present in the stomach
- D. secreted in an inactive form
Correct Answer: D
Rationale: Protein-digesting enzymes like pepsinogen and trypsinogen are secreted in an inactive form and activated later.
Saliva contains two enzymes. What are they?
- A. Amylase and pepsin
- B. Amylase and lysozyme
- C. Amylase and lipase
- D. Amylase and renin
Correct Answer: B
Rationale: Saliva contains salivary amylase (ptyalin) for starch digestion and lysozyme for antibacterial action. Pepsin is in the stomach, lipase is mainly pancreatic, and renin is unrelated to saliva.