ATI Fluid and Electrolytes

Correct Answer: B

Rationale: Iodine is the correct answer because it is essential for the synthesis of thyroid hormones. The thyroid gland incorporates iodine into thyroid hormones such as thyroxine (T4) and triiodothyronine (T3). These hormones are crucial for regulating metabolism, growth, and development. Sodium, iron, and chloride are not directly involved in the formation of thyroid hormones, making them incorrect choices.

Correct Answer: A

Rationale: The correct answer is the kidneys. The kidneys are primarily responsible for regulating fluid balance by filtering blood and adjusting the volume and concentration of urine. The lungs primarily regulate gas exchange, not fluid balance. The skin plays a role in temperature regulation and protection but is not the primary organ for fluid output. The intestines are mainly involved in the absorption of nutrients and water, rather than fluid output.

Correct Answer: C

Rationale: Aldosterone increases the reabsorption of sodium in the kidneys, which leads to an increase in blood volume and blood pressure. Choice A is incorrect as aldosterone does not regulate body temperature. Choice B is incorrect as aldosterone increases blood pressure by increasing sodium reabsorption. Choice D is incorrect as aldosterone promotes water retention by increasing sodium reabsorption.

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: D

Rationale: Assessing the specific gravity in a patient with SIADH helps the nurse evaluate the patient's fluid volume status. Specific gravity indicates the concentration of solutes in the urine and can detect if the patient has a fluid volume deficit or excess. Nutritional status, potassium balance, and calcium balance are not directly assessed through specific gravity testing. Nutritional status is typically evaluated through dietary intake and anthropometric measurements. Potassium balance is assessed through blood tests and ECG monitoring. Calcium balance is evaluated through blood tests and bone density scans. Therefore, the correct answer is assessing fluid volume status through specific gravity testing.