Mucus is produced by the salivary glands and the:
- A. intestinal glands.
- B. esophageal glands.
- C. pineal gland.
- D. islets of Langerhans.
Correct Answer: A
Rationale: Mucus is produced by the salivary glands to moisten food and aid in swallowing. Additionally, the intestinal glands secrete mucus to protect the lining of the intestines. The other choices, esophageal glands, pineal gland, and islets of Langerhans, are not involved in the production of mucus in the digestive system.
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Which term describes the amino acids that are synthesized by the body?
- A. essential amino acids.
- B. nonessential amino acids.
- C. complete amino acids.
- D. incomplete amino acids.
Correct Answer: B
Rationale: The correct answer is B: nonessential amino acids. Nonessential amino acids can be synthesized by the body, so they do not need to be obtained through the diet. Essential amino acids, choice A, must be obtained from the diet because the body cannot produce them. Choices C and D, complete and incomplete amino acids respectively, do not accurately describe the classification of amino acids based on synthesis by the body.
In a low-carbohydrate diet, most of the calories are supplied by:
- A. proteins.
- B. fats.
- C. carbohydrates.
- D. vitamins.
Correct Answer: B
Rationale: In a low-carbohydrate diet, fats become the primary source of calories as carbohydrate intake is restricted. Proteins can contribute to caloric intake but are not the primary source in a low-carbohydrate diet. Carbohydrates are intentionally limited in this diet, so they do not supply most of the calories. Vitamins are essential nutrients but do not provide calories.
The type of protein-energy malnutrition (PEM) that develops when the diet lacks protein is called:
- A. kwashiorkor.
- B. marasmus.
- C. anemia.
- D. beriberi.
Correct Answer: A
Rationale: The correct answer is A: kwashiorkor. Kwashiorkor is a form of protein-energy malnutrition that arises due to a protein-deficient diet. This condition leads to symptoms such as edema, skin lesions, and fatty liver. Choice B, marasmus, is a form of PEM caused by overall malnutrition (protein and calorie deficiency), resulting in severe wasting and muscle loss. Choice C, anemia, is a condition characterized by a deficiency of red blood cells or hemoglobin, not specifically related to protein deficiency. Choice D, beriberi, is a disease caused by thiamine (Vitamin B1) deficiency, not a form of PEM related to protein deficiency.
Where does the absorption of most nutrients occur?
- A. Large intestine.
- B. Small intestine.
- C. Stomach.
- D. Mouth.
Correct Answer: B
Rationale: The absorption of most nutrients occurs in the small intestine. This is where digested food is broken down further and absorbed into the bloodstream through the intestinal walls. The large intestine primarily absorbs water and electrolytes, while the stomach mainly aids in digestion by breaking down food with gastric juices. The mouth is responsible for the initial mechanical breakdown of food through chewing and the enzymatic action of saliva, but absorption does not occur there.
What triggers the release of cholecystokinin (CCK)?
- A. Presence of food in the stomach.
- B. Presence of fat in the duodenum.
- C. Entry of acid chyme into the ileum.
- D. Entry of bile into the gallbladder.
Correct Answer: B
Rationale: The correct answer is B: Presence of fat in the duodenum. Cholecystokinin (CCK) is released in response to the presence of fat in the duodenum to aid in digestion by stimulating the release of bile from the gallbladder and enzymes from the pancreas. Options A, C, and D are incorrect because CCK is specifically released in response to the presence of fat in the duodenum, not food in the stomach, acid chyme in the ileum, or bile in the gallbladder.