How oxygen and carbon dioxide are exchanged in the lungs tissues?

Oxygen and carbon dioxide are exchanged in the lungs and tissues through the process of respiration. Respiration involves two main stages:

1. Pulmonary Ventilation:

- Inhalation: During inhalation, the diaphragm and intercostal muscles contract, causing the chest cavity to expand and the lungs to fill with air. Oxygen-rich air enters the lungs through the nose or mouth, passes through the trachea, and then into the bronchi and bronchioles.

- Exhalation: During exhalation, the diaphragm and intercostal muscles relax, causing the chest cavity to recoil and the lungs to deflate. Carbon dioxide-rich air is expelled from the lungs through the bronchioles, bronchi, trachea, and out through the nose or mouth.

2. Gas Exchange:

- In the Lungs: Oxygen from the inhaled air diffuses across the thin walls of the alveoli (tiny air sacs in the lungs) into the bloodstream, while carbon dioxide diffuses from the bloodstream into the alveoli. The oxygen-rich blood is then pumped by the heart to the rest of the body.

- In the Tissues: In the tissues, the oxygen from the bloodstream diffuses into the cells, while carbon dioxide diffuses from the cells into the bloodstream. The carbon dioxide-rich blood is then returned to the lungs to be exhaled.

This continuous process of gas exchange ensures that the body's cells receive the oxygen they need to function and that carbon dioxide, a waste product of cellular respiration, is removed from the body.