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: 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: B

Rationale: The symptoms described, including tingling in the lips and fingers, intermittent spasms, and increased muscle tone, are indicative of tetany, which is a common manifestation of hypocalcemia. Hypocalcemia can lead to neuromuscular irritability, causing symptoms such as paresthesias and muscle spasms. Hypophosphatemia primarily affects the central nervous system, resulting in seizures and coma. Hypermagnesemia typically presents with hypoactive reflexes and somnolence. Hyperkalemia can cause paresthesias and anxiety, but in this case, the patient's symptoms are more suggestive of hypocalcemia.

Correct Answer: B

Rationale: The correct answer is B, Interstitial fluid. Interstitial fluid is the fluid that surrounds and occupies the spaces between cells, providing them with nutrients and removing waste. Choices A, C, and D are incorrect because intracellular fluid refers to fluid inside cells, plasma refers to the liquid component of blood, and electrolyte refers to substances that dissociate into ions in solution, affecting fluid balance but not specifically found in spaces between cells.

Correct Answer: B

Rationale: The correct answer is Potassium (K+). Potassium is the predominant cation found within cells, making it the most prevalent positive ion in intracellular fluid. Calcium, sodium, and magnesium are also essential ions in the body, but they are not as abundant in intracellular fluid. Calcium is vital for bone health and muscle function, sodium helps in maintaining fluid balance and nerve function, and magnesium is involved in numerous biochemical reactions.