The process of inspiration begins in the brain
The brain's breathing center ordered the diaphragm and the breathing muscles to contract. When the breathing muscles contract, the ribs move to the top and to the sides. The contraction of the diaphragm, coupled with constriction of the breathing muscles, leads to the enlargement of the rib cage. In the aftermath, the lungs also widen, the volume increases and the air pressure decreases. The pressure differential between the air outside and between the air in the lungs leads to the entry of air that is outside to the lungs. The oxygen in the air spreads through the walls of the vesicles into the blood that is carried in the peripheral blood vessels of the vesicles. From there it is transferred to all parts of the body.
The brain's breathing center ordered the diaphragm and the breathing muscles to contract. When the breathing muscles contract, the ribs move to the top and to the sides. The contraction of the diaphragm, coupled with constriction of the breathing muscles, leads to the enlargement of the rib cage. In the aftermath, the lungs also widen, the volume increases and the air pressure decreases. The pressure differential between the air outside and between the air in the lungs leads to the entry of air that is outside to the lungs. The oxygen in the air spreads through the walls of the vesicles into the blood that is carried in the peripheral blood vessels of the vesicles. From there it is transferred to all parts of the body.