Physical Therapy Assistant Practice Exam

How do diuretic agents primarily decrease blood pressure?

1. By thickening blood viscosity

2. By increasing sodium and water excretion

3. By increasing heart rate

4. By relaxing blood vessel walls

The correct answer is: By increasing sodium and water excretion

Diuretic agents primarily decrease blood pressure by increasing the excretion of sodium and water from the kidneys. This mechanism leads to a reduction in the volume of blood circulating in the bloodstream. When excess sodium is eliminated, it also draws water out of the body, which further reduces blood volume. Lower blood volume translates to decreased pressure on the arterial walls, contributing to a reduction in overall blood pressure. The effectiveness of diuretics in managing hypertension is significant because they target the body's fluid balance. By lowering circulating blood volume, they help in managing hypertension and can be an essential part of treatment regimens for patients with high blood pressure. The other options do not accurately describe how diuretics function. Thickening blood viscosity would likely increase blood pressure, and increasing heart rate would not directly correlate with blood pressure lowering. Relaxing blood vessel walls is more characteristic of vasodilators than diuretics. Thus, the role of diuretics is specifically linked to the elimination of excess fluid and sodium, making the choice about increasing sodium and water excretion the correct approach to understanding how they work to lower blood pressure.