How body alters air pressure in lungs?

The body alters air pressure in the lungs through the process of respiration, which involves both inspiration and expiration. Here's how the body changes air pressure in the lungs:

Inspiration (Inhaling):

1. Diaphragm Contraction: During inhalation, the diaphragm, a large muscle located at the base of the lungs, contracts and moves downward. This increases the volume of the thoracic cavity, the space within the chest that houses the lungs.

2. Expansion of Lungs: As the diaphragm descends, it pulls the lungs downward and outward, causing them to expand. The expansion of the lungs creates a decrease in air pressure inside the lungs compared to the atmospheric pressure outside.

3. Airflow into Lungs: The difference in air pressure between the lungs and the atmosphere creates a pressure gradient. Air from the surrounding environment, which is at a higher pressure, flows into the lungs through the nose or mouth and down into the airways (bronchi and bronchioles). This airflow continues until the pressure inside the lungs equalizes with the atmospheric pressure.

Expiration (Exhaling):

1. Diaphragm Relaxation: During exhalation, the diaphragm relaxes and moves upward, reducing the volume of the thoracic cavity.

2. Elastic Recoil of Lungs: As the diaphragm rises, the lungs recoil passively due to their inherent elasticity. This recoil, along with the elastic properties of the chest wall, contributes to the reduction of lung volume.

3. Airflow out of Lungs: The decrease in lung volume increases the air pressure inside the lungs compared to the atmospheric pressure. This pressure gradient causes the air within the lungs to flow out through the airways, nose, and mouth. The airflow continues until the pressure inside the lungs equalizes with the atmospheric pressure.

This cycle of inspiration and expiration leads to continuous changes in air pressure within the lungs. During inspiration, the air pressure in the lungs decreases, allowing air to flow in, while during expiration, the air pressure increases, leading to the expulsion of air.