How Do We Breathe And Exchange Gases

Every living being has to breathe. Animals with breathing bring oxygen into the body. Taking air we take oxygen. Breathing seems simple. We do not even think how to breathe, although breathing consists of a very complex operations. When a person breathes air, it goes through a series of tubes in the body called respiratory tract. They begin with the nose, where it stops particles that could be harmful to the lungs. In the nose, the air is purified and heated.

Nasal air goes down through the gorge. From there, through the larynx and trachea, goes to two smaller tubes called bronchi, each of which enters to one of two lung. The lungs are large, soft bodies, and consist of two lungs, right and left. Each lung is completely enveloped in a thin blanket which is called the pleura or lung tissues.

Lung is like a sponge. It is made up of many small bit of bubbles filled with air that enters into them. Through bronchus air arrives in the lung bubbles. They can take oxygen from the air, and unnecessary gases ejected from the body. These small bubbles filled with air are called alveoli.

The air we breathe contains oxygen, nitrogen, carbon dioxide and water vapor. These gases are present in human blood, just in different amounts.

When you breathe in fresh air, then in the alveoli has more oxygen than in the blood. Therefore, the oxygen from the air passes into the blood through the very thin walls of the alveoli and the tiny blood vessels, the capillaries. Carbon dioxide is higher in the blood, but less in the the alveoli and therefore goes from the blood into the alveoli of the lungs, where it exhale.

Taking oxygen from the air and the discharge of carbon dioxide from the body allows the cells to receive oxygen and to release harmful carbon dioxide.

How much air the lungs can hold? To measure this, we must take into account normal breathing, then additional amount of air until the end of deep breaths and amount to the end of a deep exhalation. This is called vital capacity or the amount of air that the lungs can hold. A grown man has a vital capacity which amounts to little more than 4 liters of air; vital capacity of women is about 3 liters.

The lungs are never empty, even when strongly exert to exhale air. The amount of air remaining in the lungs after a maximum exhalation is called residual air, and when you inhale, residual air is mixed with fresh air.

Breathing is both willing and unwilling action. We breathe but do not think about it, like when we sleep. But we can stop breathing for a short time if we want – when hold our breath as long as we dive.