Which physiological process is associated with the beginning of inspiration?

The physiological process associated with the beginning of inspiration primarily involves the expansion of lung capacity. During inspiration, the diaphragm contracts and moves downward, which increases the volume of the thoracic cavity. This expansion creates a negative pressure within the thoracic cavity relative to the atmosphere, allowing air to flow into the lungs.

While options such as decreasing thoracic volume, increasing diaphragm tone, and elevation of the ribcage contribute to the mechanics of breathing, it is the overall expansion of lung capacity that is crucial at the onset of inspiration. This expansion not only facilitates air entry but also enhances gas exchange efficiency within the alveoli, which is vital for effective respiration.