What is the role of sodium (Na+) in the body?

Sodium (Na+) plays a vital role in maintaining the body’s water content and fluid balance. It is primarily an extracellular ion, meaning it exists outside the cells, and it is essential for regulating osmotic pressure and fluid distribution within the body. Sodium helps to draw water into the bloodstream, contributing to blood volume and overall hydration.

In addition to its role in fluid balance, sodium is crucial for proper nerve function and muscle contraction. It facilitates the transmission of electrical impulses in nerve cells and is also involved in muscle contraction processes. The delicate balance of sodium levels in the body is also important for maintaining blood pressure. However, it is not accurate to say that sodium regulates blood pressure exclusively, as it is just one of many factors involved in blood pressure regulation.

The other options suggest roles that are either not primary functions of sodium or are inaccurate. Sodium does not interfere with calcium absorption; rather, it can influence calcium excretion. Similarly, while sodium is important in kidney function and fluid balance during dialysis, it does not have a direct role in detoxifying blood. Thus, option B accurately captures the essential function of sodium in maintaining fluid balance.