ATI Fluid and Electrolytes

Correct Answer: B

Rationale: The correct answer is interstitial fluid. Interstitial fluid is the fluid that surrounds and fills the spaces between cells, facilitating nutrient and waste exchange. Plasma, referred to in choice A, is the liquid part of blood. Choice C, intracellular fluid, is the fluid inside cells. Choice D, edema, is an abnormal accumulation of fluid in interstitial spaces, causing swelling.

Correct Answer: A

Rationale: An increase in capillary blood pressure leads to a higher force pushing fluid out of the capillaries into the interstitial space, thereby increasing interstitial fluid volume. Choice B is incorrect because capillary blood pressure affects the movement of fluid into the interstitial space, not into the plasma. Choice C is incorrect as an increase in capillary blood pressure would not decrease interstitial fluid volume. Choice D is incorrect as it combines contradictory effects when capillary blood pressure increases.

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.

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.

Correct Answer: D

Rationale: Newborns have a higher percentage of body water compared to adults due to their higher body fluid content. Factors such as the higher ratio of body surface area to body volume and lower body fat content contribute to this. This is why a newborn would have the greatest percentage of body water. Choices A, B, and C are incorrect because obesity and gender do not determine the percentage of body water in individuals. Therefore, the correct answer is a newborn.