Nokea
Primary carcinoma is least common in:
- A. esophagus
- B. stomach
- C. small intestine
- D. colon
Correct Answer: C
Rationale: The correct answer is C: small intestine. Primary carcinoma is least common in the small intestine compared to the other choices. This is because the small intestine has a lower incidence of cancer compared to the esophagus, stomach, and colon. Factors contributing to this lower incidence include less exposure to carcinogens, a relatively smaller surface area, and less common inflammatory conditions that can lead to cancer development. Additionally, the small intestine has a more rapid turnover of cells, reducing the likelihood of cancerous mutations accumulating. Therefore, the small intestine is the least common site for primary carcinoma among the options provided.
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A tumor producing large amounts of gastrin DOES NOT include:
- A. Hyperplasia of gastric epithelium
- B. Hyperplasia of gastric mucosal lymphocytes
- C. Excessive gastric acid secretion
- D. Histamine secretion in the gastric mucosa
Correct Answer: B
Rationale: The correct answer is B: Hyperplasia of gastric mucosal lymphocytes. In a tumor producing large amounts of gastrin, hyperplasia of gastric epithelium (choice A) is expected due to increased gastrin stimulation. Excessive gastric acid secretion (choice C) is also expected as gastrin stimulates acid production. Histamine secretion in the gastric mucosa (choice D) can occur as histamine is released in response to gastrin. However, hyperplasia of gastric mucosal lymphocytes (choice B) is not a direct consequence of increased gastrin levels. Lymphocyte hyperplasia is more commonly associated with chronic inflammation or infection rather than gastrin overproduction.
Stimulation by the parasympathetic nervous system will cause the ______ anal sphincter to ______.
- A. external; relax
- B. external; contract
- C. internal; contract
- D. internal; relax
Correct Answer: D
Rationale: The correct answer is D because the parasympathetic nervous system is responsible for promoting rest and digest functions. The internal anal sphincter is controlled by the autonomic nervous system, specifically the parasympathetic division. When stimulated by the parasympathetic nervous system, the internal anal sphincter will relax, allowing for defecation to occur.
A: The external anal sphincter is under voluntary control, not affected by the parasympathetic nervous system.
B: The external anal sphincter contracts voluntarily, not influenced by the parasympathetic nervous system.
C: The internal anal sphincter contracts under sympathetic stimulation, not parasympathetic.
Which one of the following tissues normally DOES NOT produce ghrelin that stimulates food intake?
- A. Stomach
- B. Pancreas
- C. Adrenal
- D. Liver
Correct Answer: D
Rationale: Step 1: Ghrelin is primarily produced by the stomach to stimulate appetite.
Step 2: The pancreas produces insulin and enzymes, not ghrelin.
Step 3: The adrenal glands produce hormones like cortisol, not ghrelin.
Step 4: The liver is not a major site for ghrelin production, making choice D the correct answer.
If you suck on a plain piece of bread, it will begin to taste sweet after a few moments. Saliva contains the digestive enzyme ______ which breaks down starch into ______.
- A. amylase; glucose
- B. pepsin; maltose
- C. amylase, maltose
- D. maltase, glucose
Correct Answer: C
Rationale: The correct answer is C: amylase, maltose. Amylase is the digestive enzyme present in saliva that breaks down starch into maltose. When you suck on bread, the amylase in saliva starts breaking down the starch molecules into maltose, which is a sugar that tastes sweet. Option A is incorrect because amylase breaks down starch into maltose, not glucose. Option B is incorrect because pepsin is a stomach enzyme that breaks down proteins, not starch. Option D is incorrect because maltase is an enzyme in the small intestine that breaks down maltose into glucose, not the enzyme present in saliva.
During the gastric phase of digestion
- A. There is neural stimulation only
- B. There is decreased contractility
- C. The bolus composition is detected by chemoreceptors
- D. It only takes minutes
Correct Answer: C
Rationale: Rationale:
1. Gastric phase starts when food enters the stomach.
2. Chemoreceptors detect bolus composition to initiate gastric secretions.
3. This detection triggers release of gastric juices for digestion.
4. Neural stimulation also occurs during gastric phase, but not exclusively.
5. Contractility increases during gastric phase for mixing and churning.
In summary, choice C is correct as chemoreceptors detect bolus composition during the gastric phase, while the other choices are incorrect because they do not accurately reflect the physiological processes during this phase.