Lung

Definition

The lung (Pulmo) is the organ of the body responsible for sufficient oxygen intake and supply. It consists of two lungs that are spatially and functionally independent of each other and surrounds the heart with them. The two organs are located in the thorax, protected by the ribs. The lung has no shape of its own but is shaped in its relief by the surrounding structures (diaphragm at the bottom, heart in the middle, ribs on the outside, trachea and esophagus at the top).

Structure of the air conducting airways

To understand the anatomy of the lungs, the easiest way to understand the path of the air we breathe is to follow the path of the air we breathe: The air enters the body through the mouth or nose. Then it flows into the throat (pharynx), then into the larynx with the vocal folds. Up to this point, the air and food passages are identical.

From the passage between the vocal folds, which form the narrowest part of the upper airways, the trachea begins. During anesthesia and in emergency patients, this narrow point is bridged by a tube (breathing tube) (intubation) in order to be able to secure the supply by mechanical ventilation. From the vocal folds onwards, all subsequent sections are purely air-conducting; if foreign bodies get here, this is called aspiration, which then triggers the cough reflex.

Anatomy of air conduction sections

The trachea is located very far forward in the neck, so that it is possible to perform a tracheotomy here. This allows access to the lungs in an emergency in case of obstruction of the upper airways (e.g. vomit). The wall of the trachea consists of the ciliated cells typical of the respiratory tract.

These ciliated cells have fine hairs (kinocilia) on their surface, which they use to transport mucus and foreign bodies (e.g. bacteria) towards the mouth. The mucus contains special antibacterial substances (directed against bacteria) and is formed by another specialized cell type (so-called goblet cells). It has a mechanical and immunological (bacterial defense) protective function.

Various causes, especially cigarette smoke (smoking), irritate the ciliated cells and lead to increased mucus formation. The approx. 20 cm long trachea finally branches out in the thorax into a left and right main bronchus (Bifurcatio tracheae), which then lead into the right and left lungs respectively. The right bronchus (= branch of the lustres) is somewhat larger and runs at a steeper angle, so that swallowed foreign bodies are very likely to enter the right lung. The point at which the bronchi enter the lungs is called the hilus; the blood and lymph vessels also enter the lungs here.