Breathing Mechanism

Breathing Mechanism

The physical movements associated with the gaseous exchange are called breathing. They are controlled by the respiratory centre of the medulla oblongata in the human brain. Thus, the breathing movements are involuntary to a large extent. However, we can control the rate of breathing and the extent of breathing but not for a long time. The respiratory centre is stimulated by the carbon dioxide concentration of the blood.

There are two types of physical movements associated with the gaseous exchange. They are:

* Inspiration or inhalation

* Expiration or exhalation

Inspiration or Inhalation

During inspiration, the outer intercostal muscles contract, which raises the chest cavity or the ribs. This is accompanied by the lowering of the diaphragm. Together these movements serve to increase the area of the thoracic cavity, which reduces the pressure. The air from outside rushes into the lungs.