Explain the process of breathing in man .

Explanation

Breathing in humans involve following steps
(i) Inspiration When we breathe in , the muscles between th e ribs contract causing the rib cage to move upward and outward , and the diaphragm contracts and moves downward . As the chest cavity becomes large, air is sucked in from outside into the lungs, the lungs get filled up with air and expand.
(ii) Gaseous exchange Haemoglobin in RBCs binds with oxygen and carries it along the body , with blood . As blood passes through the tissues of the body , the oxygen from blood diffuses into the cell whereas `CO_(2)` produced during respiration diffuse into the blood and is carried to the lungs.
(iii) Expiration When we breathe out, the muscles between the ribs relax causing the rib cage to move downward and inward and the diaphragm relaxes and moves upward . As the chest cavity becomes smaller , air is pushed out from lungs.