Nokea
The pH in the mouth decreases after eating. Which statement explains the decrease in pH?
- A. Bacteria release acids when respiring food substances.
- B. Enzymes in saliva release acids during digestion.
- C. Food substances become alkaline when chewed.
- D. Salivary glands release an alkaline solution.
Correct Answer: A
Rationale: Bacterial metabolism of food releases acids, lowering the pH in the mouth.
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Which of the following secretions is NOT produced by gastric glands?
- A. hydrochloric acid
- B. intrinsic factor
- C. pepsin
- D. sebum
Correct Answer: D
Rationale: Sebum is an oily substance produced by sebaceous glands in the skin, not by gastric glands, which secrete HCl, intrinsic factor, and pepsin.
A lack of functioning salivary amylase would prevent an individual from being able to digest lactose
- A. TRUE
- B. FALSE
Correct Answer: B
Rationale: Salivary amylase digests starches, not lactose. Lactose digestion occurs in the small intestine via lactase.
Into which tubes do the nephrons drain?
- A. Proximal convoluted tubule
- B. Collecting duct
- C. Distal convoluted
- D. Ureter
Correct Answer: B
Rationale: Nephrons drain into collecting ducts, which lead to the ureter.
Which structure is the uppermost part of the alimentary canal or gastrointestinal (GI) tract?
- A. Esophagus
- B. Liver
- C. Cecum
- D. Sigmoid
Correct Answer: A
Rationale: The alimentary canal begins at the mouth, followed by the esophagus, making the esophagus the uppermost structure listed.
What role does the stomach play in the maintenance of normal vitamin B12 levels?
- A. Produces intrinsic factor
- B. Absorbs vitamin B12
- C. Stores vitamin B12
- D. Converts vitamin B12
Correct Answer: A
Rationale: The stomach's parietal cells produce intrinsic factor, necessary for vitamin B12 absorption in the ileum.