Anatomy and Physiology II Practice Test

Which of the following is NOT a source of fluid intake for the body?

1. Water from catabolism

2. Liquids consumed

3. Food eaten

4. Exhaled air

The correct answer is: Exhaled air

Fluid intake for the body is derived from several key sources that contribute to overall hydration. Water from catabolism, liquids consumed, and food eaten all serve as significant contributors to fluid intake. Water from catabolism refers to the metabolic water produced as a byproduct of biochemical reactions, particularly during the oxidation of nutrients, which generates water that the body can utilize. Liquids consumed obviously include all drinks, such as water, juices, and other beverages, which provide direct fluid intake. Food eaten also contributes to fluid intake, as many foods, especially fruits and vegetables, contain high water content that helps hydrate the body. Exhaled air does not contribute to fluid intake; rather, it results in fluid loss. When we breathe, water vapor is lost through exhalation, which can lead to dehydration if not compensated by adequate fluid intake from other sources. Therefore, identifying exhaled air as a source of fluid intake is not accurate, making it the correct answer as the option that does not represent a source of fluid intake.