ATI TEAS Practice Test 2025 – Complete Study Guide

The lungs are the primary organs responsible for gas exchange in the respiratory system. Within the lungs, tiny air sacs called alveoli facilitate the exchange of oxygen and carbon dioxide between the air we breathe and the blood. When inhaled air reaches the alveoli, oxygen passes into the bloodstream, while carbon dioxide is transferred from the blood into the alveoli to be exhaled. This process is essential for maintaining the body’s oxygen levels and removing waste gases, thus playing a crucial role in respiration and overall metabolic function.

The heart, while vital for pumping oxygenated blood to tissues and returning deoxygenated blood to the lungs, does not directly participate in gas exchange. The kidneys are involved in regulating fluid and electrolyte balance and waste elimination, and do not play a role in respiratory gas exchange. The diaphragm is a muscle that aids in the process of breathing by contracting and relaxing to allow air to flow into the lungs, but it is not the site of gas exchange itself.