What causes the greatest change in thoracic volume during quiet inspiration? What causes the greatest change in thoracic volume during quiet inspiration? Relaxation of the internal intercostal muscles Contraction of the diaphragm Increased intrapleural pressure Air flowing into the lungs
Biology · High School · Thu Feb 04 2021
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The greatest change in thoracic volume during quiet inspiration is primarily caused by the contraction of the diaphragm. When the diaphragm, a large dome-shaped muscle at the base of the lungs, contracts, it moves downward. This increases the vertical dimension of the thoracic cavity, creating a vacuum that lowers the pressure inside the thoracic cavity relative to the outside air pressure. The difference in pressure causes air to flow into the lungs.