Washington Esthetician State Board Practice Exam

Which statement accurately describes the main function of red blood cells?

1. Transporting nutrients to tissues

2. Carrying carbon dioxide away

3. Transporting oxygen to tissues

4. Regulating body fluid levels

The correct answer is: Transporting oxygen to tissues

The main function of red blood cells, or erythrocytes, is to transport oxygen to the body's tissues. This process is vital for cellular respiration, allowing for the conversion of nutrients into energy that cells can use. Red blood cells contain hemoglobin, a protein that binds to oxygen in the lungs and releases it as the blood circulates through the body. This oxygen delivery is crucial for maintaining healthy bodily functions, as cells require a constant supply of oxygen to produce energy efficiently. While some red blood cells are involved in transporting carbon dioxide back to the lungs for exhalation, their primary role is not centered around this function. Similarly, transport of nutrients is generally the responsibility of plasma in the blood rather than red blood cells themselves. Lastly, regulating body fluid levels is a function predominantly managed by the kidneys and related hormonal responses. Therefore, the correct answer highlights the essential role of red blood cells in supporting the body's respiratory needs through oxygen transport.