Class 11 NEET Biology Breathing and Exchange of Gases

The process of breathing involves the pathway of the human respiratory system and includes the nasal cavities, oral cavities, pharynx, trachea, primary bronchi, secondary bronchi and lungs with bronchioles and alveoli present. Breathing is a 2-fold process which includes breathing in and breathing out. During this process, the diaphragm which is the dome-shaped sheet of muscle located below the lungs contracts and expands along with the intercostal muscles to force air in and out of the lungs. Since intercostal muscles are also involved in the process of respiration, deeper respiration results in the movement of ribs too. Hence most of us can consciously breathe in and breathe out by moving the diaphragm alone.