How do the lungs contribute to oxygen transport in the cardiorespiratory system?

The lungs play a crucial role in the process of oxygen transport within the cardiorespiratory system primarily through the absorption of oxygen into the blood. This occurs during the process of gas exchange, which takes place in the alveoli—tiny air sacs in the lungs. When fresh air is inhaled, oxygen diffuses from the alveoli into the capillaries that surround them due to the difference in concentration gradients. The oxygen then binds to hemoglobin molecules in red blood cells and is transported throughout the body to meet the metabolic demands of tissues.

While filtering impurities from the air, regulating blood pressure, and producing carbon dioxide are important functions of the respiratory and circulatory systems, they do not directly involve the process of oxygen transport. Filtering impurities helps to ensure cleaner air reaches the lungs but is not part of the oxygen absorption mechanism. Regulating blood pressure is primarily a function of the heart and vascular system, and producing carbon dioxide is a byproduct of metabolism that is expelled through the lungs rather than contributing to oxygen transport. Thus, the absorption of oxygen into the blood is the key function of the lungs in oxygen transport within the cardiorespiratory system.