Anatomy and Physiology II Practice Test

If fluid intake equals fluid output, what happens to the total amount of water in the body?

1. It increases

2. It decreases

3. It stays the same

4. It fluctuates significantly

The correct answer is: It stays the same

When fluid intake equals fluid output, the total amount of water in the body remains constant. This balance indicates a state of homeostasis, where the body is maintaining its internal environment effectively. The body continuously exchanges fluid through various processes such as drinking, eating, sweating, urination, and respiration. When these inputs (fluid intake) match the outputs (fluid output), it means that any water consumed is being adequately processed and expelled without a net gain or loss. Thus, the overall volume of water in the body stays the same. If either fluid intake were to exceed fluid output or vice versa, it would lead to an increase or decrease in total body water, respectively. However, in the scenario described, with equal intake and output, homeostasis is achieved, and the total amount of water in the body remains stable.