What role does the chest cavity play in breathing?

The chest cavity plays a crucial role in the process of breathing, primarily through its ability to expand and relax. This action creates a change in pressure within the cavity, allowing air to flow in and out of the lungs. When the diaphragm and intercostal muscles contract, the chest cavity enlarges, leading to a decrease in pressure that draws air into the lungs (inhalation). Conversely, when these muscles relax, the chest cavity decreases in volume, increasing pressure and forcing air out of the lungs (exhalation). This fundamental mechanism is essential for effective respiration, supporting oxygen intake and carbon dioxide expulsion.

Other roles mentioned, such as speech production, maintaining body temperature, or pumping blood to the lungs, do not directly describe the mechanical function of the chest cavity in respiration. While the chest cavity may contribute to speech through the airflow produced during breathing, its primary function in the respiratory process is related to its expansion and relaxation.