What is the primary function of the lungs in the human body?

The primary function of the lungs in the human body is to facilitate the exchange of carbon dioxide for oxygen. This crucial process occurs in the alveoli, tiny air sacs within the lungs where blood takes up oxygen from the inhaled air and releases carbon dioxide, a waste product of metabolism. This exchange is essential for maintaining the body's oxygen levels, which are vital for cellular function and overall health.

Inhalation brings fresh oxygen into the lungs, while exhalation removes carbon dioxide from the bloodstream, ensuring that the body maintains a proper balance of gases. Oxygen is then transported throughout the body by the bloodstream to support various bodily functions, including energy production in cells.

While other options offer related physiological functions, they do not represent the primary responsibility of the lungs. For instance, filtering toxins from the blood is primarily a function of the liver and kidneys, regulating body temperature involves multiple systems including sweat glands and blood circulation, and digestion is managed by the gastrointestinal system. Thus, the integral role of the lungs is centered specifically on the respiratory process of gas exchange.