Describe inhalation and exhalation
Inhalation: ribs move up and out, SA of ribs increases, diaphragm flattens and contracts, volume of chest expands, pressure decreases, air moves into the lungs through the trachea. Exhalation: ribs move down and in, SA of ribs decreases, diaphragm returns to its normal curved shape, volume of chest decreases, intercostal muscles relax, pressure increases, air moves out of the lungs.
