What happens to the thoracic diaphragm during inspiration?

During inspiration, the thoracic diaphragm contracts and moves downward, which increases the volume of the thoracic cavity. This contraction creates a negative pressure within the thoracic cavity relative to atmospheric pressure, allowing air to be drawn into the lungs. As the diaphragm lowers, the lungs expand to fill the increased space, facilitating the inflow of air needed for breathing.

This process is crucial for effective respiration and highlights the diaphragm's role as the primary muscle of inspiration. When the diaphragm moves downward, it also has an effect on the abdominal cavity, leading to a downward displacement of abdominal contents. Understanding this mechanism is essential for grasping how the respiratory system operates during inhalation and the importance of the diaphragm's movement in facilitating breathing.