It is characterized by the exchange of gases between the lungs and body tissues.
The lungs' alveoli are in charge of exchanging gases between the blood and the surrounding environment.
Blood to absorb in lungs:
When we breathe in, oxygen is delivered to the alveoli of the lungs.
The partial pressure of oxygen at the alveolar site is greater than the partial pressure of carbon dioxide.
As a result, when impure blood enters the alveolar capillaries, oxygen binds to hemoglobin and forms oxyhemoglobin in the capillary blood.
Because oxyhemoglobin is acidic in nature, it aids in the breakdown of sodium bicarbonate (NaHCO3) in the blood. Carbon dioxide is produced as a result of the breakdown of NaHCO.
As a result of the high concentration of oxygen at the alveolar site, oxygen leaves the alveolar site and enters red blood cells, where it binds with hemoglobin.
Following that, pureblood carrying oxygen reaches all cells and tissues in the body, supplying oxygen for various cellular activities.
Carbon dioxide diffuses into the blood at the tissue level and reaches the alveoli of the lungs, where it is exhaled (released outside the body) through the nose.