ATI Fluid and Electrolytes

Correct Answer: D

Rationale: The correct answer is D, ADH and aldosterone. Both antidiuretic hormone (ADH) and aldosterone increase water retention by the kidneys, thereby increasing blood volume. ADH acts on the kidneys to increase water reabsorption, while aldosterone acts on the kidneys to promote sodium reabsorption, leading to water retention. Choice A, ADH, is partially correct as it alone increases water retention. Choice B, aldosterone, is also partially correct as it alone increases water retention. Choice C, ANH (atrial natriuretic hormone), actually decreases water retention by promoting sodium excretion and inhibiting aldosterone release.

Correct Answer: B

Rationale: The correct answer is B. The largest volume of water in the body is found inside the cells, known as intracellular fluid. This fluid makes up the majority of the body's total water content. Choices A, C, and D are incorrect because while plasma, interstitial fluid, and lymph are important components of the body's fluid compartments, they do not contain the largest volume of water in the body.

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.

Correct Answer: A

Rationale: The correct answer is A: 80%. Newborns can have a body water content as high as 80% due to their higher total body water compared to adults. Choice B (70%) is incorrect because newborns typically have a higher body water percentage. Choice C (60%) is also incorrect as it underestimates the body water content in newborns. Choice D (90%) is incorrect as it overestimates the body water percentage in newborns.

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.