Nokea
The muscular contractions, which move material through the digestive tract, are called:
- A. peristalsis
- B. deglutition.
- C. mass movements.
- D. segmental contractions.
Correct Answer: A
Rationale: The correct answer is A: peristalsis. Peristalsis refers to the wave-like muscular contractions that propel food through the digestive tract. First, circular muscles contract behind the food bolus creating a narrowing, then longitudinal muscles contract ahead of the bolus, pushing it forward. This coordinated movement helps move food along the digestive tract efficiently. Deglutition (B) refers to the act of swallowing, not the movement of food through the digestive tract. Mass movements (C) refer to large, powerful contractions that occur in the colon to move feces. Segmental contractions (D) are localized contractions that mix and churn food in the intestines, not the primary mechanism for moving food along the digestive tract.
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The nurse is caring for a patient who complains, "I don't see why I can't have a CT scan instead of the expensive MRI!" Which response is most appropriate for the nurse to make?
- A. "The MRI provides better contrast between normal and pathologic tissue."
- B. "The MRI requires less analysis and is easier to read."
- C. "The MRI produces a digital image that can be transmitted via email."
- D. "The MRI exposes the patient to less radiation."
Correct Answer: A
Rationale: The correct answer is A because MRI provides better contrast between normal and pathologic tissue compared to CT scans. This allows for more accurate diagnosis and treatment planning. Choice B is incorrect because MRI images are typically more complex and require specialized analysis. Choice C is incorrect because both CT and MRI images can be transmitted digitally. Choice D is incorrect because CT scans actually expose patients to less radiation compared to MRI.
The function of the gastrointestinal tract can be classified in several ways. Which of the following functions is most important for survival immediately after a meal?
- A. Absorption and retention of water and electrolytes
- B. Elimination of toxins
- C. Maintenance of barrier function
- D. Extraction of maximum value from nutrients
Correct Answer: A
Rationale: The correct answer is A: Absorption and retention of water and electrolytes. Immediately after a meal, the body needs to absorb water and electrolytes to maintain proper hydration and electrolyte balance, crucial for survival. This process helps in nutrient absorption and maintaining overall body function.
Reasons for why the other choices are incorrect:
B: Elimination of toxins - While important for overall health, elimination of toxins is not the most critical function immediately after a meal for survival.
C: Maintenance of barrier function - While important for protecting against harmful substances, it is not the most vital function immediately after a meal for survival.
D: Extraction of maximum value from nutrients - While important for optimal nutrition, it is not as crucial as absorption and retention of water and electrolytes for immediate survival post-meal.
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.
Which hormone stimulates the release of digestive enzymes from the pancreas?
- A. Insulin
- B. Glucagon
- C. Secretin
- D. Cholecystokinin (CCK)
Correct Answer: D
Rationale: The correct answer is D, Cholecystokinin (CCK). CCK is produced in the small intestine in response to the presence of fats and proteins. It stimulates the release of digestive enzymes from the pancreas to aid in digestion. Insulin (A) and Glucagon (B) are involved in regulating blood sugar levels, not digestive enzyme release. Secretin (C) primarily stimulates the release of bicarbonate from the pancreas to neutralize stomach acid, not digestive enzymes.
Which of the following is not readily absorbed in the small intestine?
- A. Na+
- B. Cl-
- C. K+
- D. Mg++
Correct Answer: D
Rationale: The correct answer is D, Mg++. Magnesium is not readily absorbed in the small intestine due to its reliance on active transport mechanisms and limited absorption sites. Na+, Cl-, and K+ are all readily absorbed in the small intestine through passive or active transport processes. Na+ is mainly absorbed through active transport, Cl- through passive diffusion, and K+ through both passive and active transport mechanisms. Therefore, Mg++ stands out as it requires specific carriers for absorption, making it less readily absorbed compared to the other ions.