question_answer 109)

    Explain the process of breathing in man.

Answer:

  Breathing in humans involve following steps (i)Inspiration When we breathe in, the muscles between the ribs contract causing the ribcage to move upward and outward, and the diaphragm contracts and moves down ward, 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 Hemoglobin 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 CO2produced 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 ribcage to move downward and inward and the diaphragm relaxes and moves upward. As the chest cavity becomes smaller, air is pushed out from the lungs.