What is the primary function of the respiratory system?

The primary function of the respiratory system is to supply oxygen to the blood while removing carbon dioxide. This vital physiological process, known as gas exchange, occurs in the alveoli of the lungs, where oxygen from inhaled air passes into the bloodstream and carbon dioxide is expelled from the blood to be exhaled. This function is crucial because oxygen is necessary for cellular metabolism, enabling cells to generate energy, while the removal of carbon dioxide helps maintain pH balance in the body and prevents toxicity.

While other systems contribute to various functions of the body, such as temperature regulation, digestion, and hormone production, they do not pertain to the fundamental role of the respiratory system. The other options refer to functions that are characteristic of different bodily systems: body temperature regulation is primarily managed by the integumentary and circulatory systems, digestion and nutrient absorption fall under the purview of the digestive system, and hormone production is a function of the endocrine system. Thus, the focus on the respiratory system clearly highlights its essential role in gas exchange as foundational to sustaining life.