The lungs: structure and function

The lungs structure and function

The lungs structure and function, How does our breathing system work?

The lungs, together with the heart and the large blood vessels, lie in the chest cavity. It consists of the right and the left lung wing. The lung wings are further subdivided into so-called lung lobes, which in turn are divided into several lung segments.

When inhaled, the air flows through the nose or mouth, throat and larynx into the air tube. The air tube is an elastic tube about ten to twelve centimeters long, which runs down from the larynx into the thoracic cavity and divides into the two main bronchi. Each main bronchus supplies a lung wing with breathing air. It divides itself like the branches of a tree into ever smaller branches. This results in the lung segments. Within the segments, the bronchial tubes branch out and finally open into small pulmonary vesicles, called alveoli.

The lungs: structure and function

Through the walls of these alveoli, about 300 million in number, the gas exchange takes place: Here, oxygen is absorbed into the blood and vice versa carbon dioxide, a waste product of the body cells, is released from the blood to the air. With the blood stream, the vital oxygen enters the body cells where it is used for energy production.

The air-tubes and the bronchi are lined with a mucous membrane. This is covered with a tight hem by moving cilia which ensure that small dust particles or other foreign bodies, which have entered the air tube and stick to the slimy surface, are transported back out of the airways.

Lung function affects performance

An adult human being breathes in and out at about twelve to fifteen times a minute. At each breath, about half a liter of air is inhaled. It can be breathed faster and deeper. The physical capacity depends on the function of the lung, the so-called lung function. If the lung is unable to deliver the extra oxygen required during exertion, one feels a lack of air.

The pulmonary function – which can be measured with the aid of various breath tests – plays a decisive role when, for example, parts of the lung are surgically removed because of a tumor or larger parts of the lung have to be irradiated. A healthy lung with sufficient reserve power can generally compensate for the loss of lung tissue. If, however, the pulmonary function is already restricted, for example due to chronic bronchitis due to a strong consumption of tobacco, this can possibly preclude surgery.
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