Basic information | Respiratory tract | Lower respiratory system | The Lung

The lung

Humans and therefore each individual cell of the human body require oxygen in order to survive. Without oxygen humans are condemned to death.
In the lung oxygen is removed from the air and transferred into the blood. Bound up with red blood cells the oxygen reaches the body cells together with the blood. In response carbon dioxide, a waste product of metabolism is expired into the air through the lung.

Tasks of the lung

The intake of oxygen and the discharge of carbon dioxide must take place within A VERY SHORT TIME between inhaling and exhaling. The prerequisite for this "high-speed performance" is that as much air as possible arrives in the lung in as short a time as possible. Thus a large surface area must be available so that the respective gases can be exchanged quickly.
An example may help to understand this - imagine a large port. The more quay ports available, the more shipments can be quickly loaded and unloaded. Similarly, the fact that the lungs cover a large area enables air exchange to take place efficiently in the lungs. The miracle of "respiration" is made possible by the complex structure of the lung.

Structure of the lung

The lung can be compared to an upside down tree that is built into the thorax. The trunk and the branches correspond to the trachea and bronchi. At the end leaves hang which correspond to the alveoli.
The respiratory system is designed to absorb the fresh, i.e. oxygen-rich, air and transport it to the unimaginably large number of alveoli. The exchange of gas takes place in the alveoli. The spent air - a part of the contained oxygen is removed and carbon dioxide IS ADDED -and then breathed out.