Under normal circumstances, the kidneys provide the greatest means of water loss. Which organ provides the second greatest means of water loss?
- A. Skin
- B. Lungs
- C. Intestines
- D. Muscles
Correct Answer: A
Rationale: The correct answer is A: Skin. After the kidneys, the skin is the second largest route of water loss through perspiration. Choice B, Lungs, is incorrect as the lungs primarily exchange gases and do not play a significant role in water loss. Choice C, Intestines, is also incorrect as water loss through the intestines is minimal since most water is reabsorbed during digestion. Choice D, Muscles, is incorrect as muscles are not a major source of water loss in the body.
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The term used to describe a blood sodium level of more than 145 mEq/L is:
- A. hyponatremia.
- B. hyperkalemia.
- C. hypernatremia.
- D. hypercalcemia.
Correct Answer: C
Rationale: The correct answer is C: hypernatremia. Hypernatremia refers to an elevated level of sodium in the blood, specifically when it is more than 145 mEq/L. Choice A, hyponatremia, is incorrect as it refers to low sodium levels. Choice B, hyperkalemia, is incorrect as it refers to high potassium levels, not sodium. Choice D, hypercalcemia, is also incorrect as it relates to elevated calcium levels, not sodium.
Retention of electrolytes (especially sodium) in the interstitial fluid can result from:
- A. decreased aldosterone secretion.
- B. increased ADH secretion.
- C. increased aldosterone secretion.
- D. decreased ADH secretion.
Correct Answer: C
Rationale: The correct answer is C: increased aldosterone secretion. Aldosterone, a hormone produced by the adrenal glands, increases sodium reabsorption in the kidneys, leading to retention of sodium and water in the interstitial fluid. Increased aldosterone secretion enhances the reabsorption of sodium, thereby increasing its retention. Choice A is incorrect because decreased aldosterone secretion would lead to less sodium reabsorption and increased excretion. Choice B is incorrect because increased ADH secretion primarily affects water reabsorption rather than sodium. Choice D is incorrect because decreased ADH secretion would lead to increased water excretion but not necessarily affect sodium retention.
What happens first in dehydration?
- A. Intercellular fluid volume drops first.
- B. Plasma volume drops first.
- C. Interstitial fluid drops first.
- D. Neither interstitial nor intracellular fluid volume are affected.
Correct Answer: C
Rationale: In dehydration, the body first draws fluid from the interstitial space to maintain blood volume, leading to a decrease in interstitial fluid volume. This is why choice C is correct. Choice A is incorrect because intracellular fluid is not the first to be affected. Choice B is also incorrect as plasma volume reduction typically occurs after interstitial fluid loss. Choice D is incorrect as dehydration impacts both interstitial and intracellular fluid volumes.
Which electrolyte is important in the formation of the thyroid hormones?
- A. Sodium
- B. Iodine
- C. Iron
- D. Chloride
Correct Answer: B
Rationale: Iodine is the correct answer because it is essential for the synthesis of thyroid hormones. The thyroid gland incorporates iodine into thyroid hormones such as thyroxine (T4) and triiodothyronine (T3). These hormones are crucial for regulating metabolism, growth, and development. Sodium, iron, and chloride are not directly involved in the formation of thyroid hormones, making them incorrect choices.
Which of the following statements is correct?
- A. People with less body fat have more body water.
- B. Infants have more water per pound than adults.
- C. Females have more body water per pound than males.
- D. Infants have the same water content per pound as adults.
Correct Answer: A
Rationale: The correct statement is that people with less body fat have more body water. This is because fat tissue contains less water compared to lean tissue, so individuals with less body fat generally have a higher percentage of body water. Choice B is incorrect as infants actually have more water per pound than adults due to their higher body water content. Choice C is incorrect as males typically have more body water per pound than females. Choice D is incorrect as infants have a higher water content per pound compared to adults.