Explain the process of respiration.

Explanation

In human, respiration has two stages, such as inspiration and expiration. Inspiration is the movement of oxygen (air) into the lungs. During inhalation, ribs are lifted up and diaphragm becomes flattened. As a result, volume of chest cavity increases, reducing the pressure inside. Thus, air from outside (region with high pressure) enters lungs (region with low pressure). When oxygen-rich air reaches alveoli, oxygen is exchanged with carbon dioxide in blood. This oxygen is carried to different parts of the body. Expiration is the process of release of carbon dioxide out of the lungs. During exhalation, ribs and diaphragm move to their original position.