What is the primary function of the respiratory system?

The primary function of the respiratory system is gas exchange between the blood and the environment. This process involves inhaling oxygen from the atmosphere into the lungs, where it diffuses into the bloodstream. Simultaneously, carbon dioxide, which is a waste product of cellular metabolism, is transferred from the blood into the lungs and exhaled into the environment. This exchange is critical for maintaining adequate oxygen levels in the body for cellular functions and for the removal of carbon dioxide, which is essential for maintaining the body's acid-base balance.

The other functions listed are not attributes of the respiratory system. Digestion is primarily handled by the gastrointestinal system, the regulation of body temperature involves the integumentary and circulatory systems, and hormone production is largely the domain of the endocrine system. Focusing on the role of gas exchange highlights the vital importance of the respiratory system in sustaining life and supporting cellular processes that depend on oxygen.