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: 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: C

Rationale: The correct answer is C: Sodium. Sodium (Na+) is the most abundant cation in the extracellular fluid, including blood plasma. It plays a crucial role in maintaining fluid balance, nerve function, and is essential for various physiological processes. Choice A, Potassium, is also an important ion in the body but is predominantly found intracellularly. Choice B, Calcium, is an essential mineral in the body but is not the most abundant positive ion in blood plasma. Choice D is incorrect as sodium is the primary positive ion in blood plasma, with a much higher concentration compared to potassium.

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: A decrease in blood protein concentration would lead to a reduction in osmotic pressure, which is responsible for drawing fluid back into the capillaries. This decrease in osmotic pressure would result in an increase in interstitial fluid volume as fluid moves out of the capillaries, and a decrease in blood plasma volume as less fluid is drawn back into the circulation. Therefore, the correct answer is to increase interstitial fluid volume and decrease blood plasma volume. Choices A, B, and C are incorrect because they do not reflect the impact of decreased blood protein concentration on fluid volumes.