Nursing Elites

1. Each of the following describes the physiologic roles of water, except one. Which is the exception?

• A. Acts as a solvent for chemical reactions.
• B. Maintains stability of body fluids.
• C. Enables transport of nutrients and excretion of waste.
• D. Regulates temperature by pooling as perspiration on skin.

Correct answer: D

Rationale: The correct answer is D. Water regulates body temperature by evaporating as perspiration from the skin, not by pooling. When sweat evaporates from the skin, it takes away heat, which helps cool the body. Choices A, B, and C are correct because water acts as a solvent for chemical reactions, maintains the stability of body fluids, and enables the transport of nutrients and excretion of waste, respectively.

2. Each statement is true of calcium within saliva, except one. Which is the exception?

• A. Saliva is supersaturated with calcium.
• B. Saliva is a source of calcium to mineralize an immature or demineralized enamel surface.
• C. Calcium and phosphate in saliva provide a buffering action.
• D. Calcium within saliva increases dental caries.

Correct answer: D

Rationale: The correct answer is D. Calcium within saliva does not increase dental caries; in fact, the buffering action provided by calcium and phosphate in saliva inhibits caries formation by preventing the dissolution of enamel by plaque biofilm. Choice A is correct as saliva is indeed supersaturated with calcium. Choice B is correct as saliva serves as a source of calcium to mineralize an immature or demineralized enamel surface. Choice C is correct as calcium and phosphate in saliva do provide a buffering action to protect teeth from acids.

3. What physiologic role does calcium play in the body?

• A. Blood clotting, transmission of nerve impulses, muscle contraction and relaxation
• B. Calcium homeostasis, structural integrity of heart muscle
• C. No known metabolic function, caries-preventing properties
• D. ATP energy release; metabolism of fats, carbohydrates, proteins; regulates acid-base balance.

Correct answer: A

Rationale: The correct answer is A: 'Blood clotting, transmission of nerve impulses, muscle contraction and relaxation.' Calcium plays a crucial role in various physiological functions such as blood clotting, transmission of nerve impulses, muscle contraction and relaxation, membrane permeability, and activation of certain enzymes. Choice B is incorrect because while calcium is involved in calcium homeostasis, it is not the only role it plays in the body. Choice C is incorrect as calcium indeed has several known metabolic functions, and it is not solely for preventing caries. Choice D is also incorrect as the functions mentioned are primarily carried out by other nutrients and not specifically by calcium.

4. Which nutrient is most important for maintaining fluid balance in the body?

• A. Protein
• B. Sodium
• C. Calcium
• D. Vitamin C

Correct answer: B

Rationale: Sodium plays a key role in maintaining fluid balance and regulating blood pressure.

5. The RDA for iron is higher in premenopausal women than for men or postmenopausal women because of the blood loss during menstruation.

• A. Both the statement and the reason are correct and related.
• B. Both the statement and the reason are correct but are not related.
• C. The statement is correct, but the reason is not correct.
• D. The statement is not correct, but the reason is correct.

Correct answer: A

Rationale: Both the statement and the reason are correct and related. The Institute of Medicine (IOM) recommends 18 mg of iron per day for women 19 to 50 years old, 8 mg/day for women 51 years old and older, and men 19 years old and older. During menstruation, women lose blood containing iron, leading to a higher iron requirement in premenopausal women compared to men or postmenopausal women. This increased demand aims to replenish the iron lost during this physiological process. Therefore, the statement and reason are directly linked, explaining why the RDA for iron is higher in premenopausal women than in men or postmenopausal women. Choices B, C, and D are incorrect as they do not accurately assess the relationship between the statement and the reason provided in the question.

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