Oregon Certified Nursing Assistant State Practice Exam

What is the primary function of the respiratory system?

1. Transporting nutrients throughout the body

2. Bringing oxygen into the body and removing carbon dioxide

3. Filtering waste from the bloodstream

4. Regulating hormones in the body

The correct answer is: Bringing oxygen into the body and removing carbon dioxide

The primary function of the respiratory system is to facilitate gas exchange, specifically bringing oxygen into the body and removing carbon dioxide. This process occurs in the lungs, where oxygen from the inhaled air diffuses into the bloodstream, and carbon dioxide, a waste product generated by cellular metabolism, is expelled from the body when exhaling. Adequate oxygen supply is crucial for cellular function and overall energy production, while the removal of carbon dioxide prevents respiratory acidosis and maintains pH balance in the body. In contrast to this, transporting nutrients throughout the body is primarily the role of the circulatory system, which distributes oxygen, nutrients, and hormones to cells and removes waste products. Filtering waste from the bloodstream is the responsibility of the renal system, particularly the kidneys, which play a key role in regulating fluid and electrolyte balance as well as excreting waste. Lastly, the regulation of hormones in the body is primarily carried out by the endocrine system, which releases hormones that coordinate various physiological processes. Thus, the respiratory system's core function is specifically about gas exchange, making the correct choice the one focused on oxygen and carbon dioxide.