How does the thoracic cavity contribute to respiration?

The thoracic cavity plays a critical role in respiration primarily because it houses the lungs and heart, which are essential for both respiratory and circulatory functions. The lungs are located within this cavity and are surrounded by pleural membranes, creating a pressure gradient necessary for inhalation and exhalation. When the diaphragm and intercostal muscles contract, the thoracic cavity expands, decreasing the pressure inside the lungs relative to the external atmosphere, allowing air to flow in. Additionally, the heart, also located in the thoracic cavity, pumps oxygenated blood received from the lungs to the rest of the body. This anatomical arrangement supports the essential functions of breathing and circulation, highlighting the interconnectedness of the respiratory and circulatory systems.