What happens to thoracic volume during inspiration?

During inspiration, the thoracic volume increases as a result of the muscular actions involved in the breathing process. The diaphragm, which is the primary muscle of respiration, contracts and moves downward, while the intercostal muscles between the ribs also contract, elevating the rib cage. This coordinated expansion of the thoracic cavity creates a negative pressure within the lung pleura, allowing air to flow into the lungs from the atmosphere.

As the thoracic volume increases, the pressure inside the thoracic cavity drops relative to atmospheric pressure. This difference in pressure is what drives air into the lungs, enabling gas exchange to occur. The increase in thoracic volume is crucial for the effective inhalation of air, and it plays a vital role in proper respiratory function. Thus, the statement that thoracic volume increases during inspiration accurately captures the physiological changes that take place during this phase of the respiratory cycle.