Nokea
Surface epithelium of gastric mucosa:
- A. Secretes acidic mucous to form a protective gel
- B. Secretes neutral to alkaline mucus rich in bicarbonate to form a protective gel
- C. Shows basal basophilia & apical acidophilia
- D. Have pale cytoplasm & flattened basal nuclei
Correct Answer: B
Rationale: The gastric surface epithelium secretes neutral to alkaline mucus with bicarbonate to protect the mucosa from acid and pepsin.
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Which statement about chemical digestion in the human alimentary canal is correct?
- A. Digestion of carbohydrates is completed in the colon.
- B. Enzymes are secreted to break down cellulose in the duodenum.
- C. Protein digestion is completed in the ileum.
- D. The stomach secretes enzymes to break down starch.
Correct Answer: C
Rationale: Protein digestion begins in the stomach with pepsin and is completed in the ileum by proteolytic enzymes from the pancreas and intestinal mucosa.
Fungiform papillae are most numerous in:
- A. Pharyngeal part of the tongue [post. 1/3rd]
- B. Oral part of the tongue
- C. Edges & tip of tongue.
- D. Basolateral area of oral part of the tongue.
Correct Answer: B
Rationale: Fungiform papillae are scattered across the oral part of the tongue but are most concentrated at the edges and tip, where taste perception is heightened.
Crypts of Lieberkuhn are found in between the villi. They secrete :
- A. Glucagon
- B. Succus entericus
- C. Insulin
- D. Gastric juice
Correct Answer: B
Rationale: Crypts of Lieberkuhn secrete succus entericus for intestinal digestion.
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.
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.