Describe the mechanism of inhalation and exhalation.

The acts of inhalation and exhalation are carried out due to the difference in atmospheric and pulmonary pressure, contraction and relaxation of the intercostal muscles and the diaphragm. Impulses from the hypothalamus are sent to the intercostal muscles and diaphragm, which leads to tension. At the same time, the volume of the chest increases, the lungs expand, their pressure drops and air is, as it were, pumped into the chest cavity. After the reverse mechanism is triggered. Nerve impulses send a signal to relax the muscles, the chest gradually decreases in volume, which leads to an increase in pressure and the expulsion of air from the lungs.