ATI Fluid and Electrolytes

Correct Answer: A

Rationale: The correct answer is A: Kidneys. The kidneys play a crucial role in regulating the amount of sodium in the body. They achieve this by filtering blood and controlling the excretion or reabsorption of sodium. The small intestine is primarily responsible for nutrient absorption, not sodium regulation. The large intestine is mainly involved in water absorption and waste elimination, not sodium balance. The skin helps regulate body temperature through sweating and does not directly regulate sodium levels.

Correct Answer: C

Rationale: The correct answer is C: 'plasma and interstitial fluid.' Extracellular fluid consists of all body fluids outside the cells, primarily including plasma (the liquid component of blood) and interstitial fluid (the fluid between cells). Choices A, B, and D are incorrect because intracellular fluid is located within the cells, not in the extracellular fluid compartment.

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: 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: D

Rationale: The correct answer is D, ADH (Antidiuretic hormone). ADH is produced by the pituitary gland and functions to increase water reabsorption in the kidneys. Choices A, B, and C are incorrect as they do not refer to a hormone responsible for increasing water absorption in the kidney.