Where is the respiratory system located

breathing

What is breathing

Breathing is the vital process in which oxygen is taken from the air (external breathing) and transported to all body cells, where it is used to generate energy (internal breathing). This creates water and carbon dioxide as waste products. The latter is released into the exhaled air in the lungs and thus removed from the body. But how does human breathing work in detail?

External breathing

The so-called external breathing (lung breathing) happens in the lungs. It describes the absorption of oxygen from the air we breathe and the release of carbon dioxide into the air we breathe. The whole thing is controlled by the breathing center in the brain. In detail, external breathing works as follows:

Oxygen-rich air flows through the mouth, nose and throat into the windpipe, where it is warmed, moistened and cleaned on its way. From the trachea it continues into the bronchi and their smaller branches, the bronchioles. At the end of the bronchioles, the air you breathe reaches the approximately 300 million alveoli. These are very thin-walled and surrounded by a network of very fine blood vessels (capillaries). The gas exchange takes place here:

The oxygen in the breath diffuses through the membrane of the alveoli into the blood, where it binds to hemoglobin (red blood pigment in the red blood cells). At the same time, the carbon dioxide diffuses from the blood into the alveoli and is then exhaled with the air.

By the way: the surface of the alveoli, through which the gas exchange takes place, covers a total area of ​​50 to 100 square meters. That is about fifty times more than the surface of the body.

The hemoglobin transports the bound oxygen with the bloodstream to all organs and to all cells that need it for energy production.

Inner breathing

Internal respiration is also called tissue respiration or cell respiration. It describes the biochemical process by which organic substances are changed (oxidized) with the help of oxygen in order to release the energy stored in the substances and make it usable in the form of ATP (adenosine triphosphate). ATP is the most important form of energy storage within cells.

In the course of internal respiration, carbon dioxide is produced as a waste product. It is transported by the blood to the lungs and exhaled there (as part of external breathing).

The respiratory muscles

The body needs the breathing muscles to inhale and exhale air. When breathing at rest, which is usually chest breathing, the diaphragm is the most important muscle for breathing in. The three rib muscles that attach to the cervical vertebrae help. The intercostal muscles only serve to stabilize the chest wall during resting breathing.

When physical work makes breathing deeper or illness makes breathing difficult, inhalation increases. Then the intercostal muscles lift the ribs and expand the chest cavity (more volume!). The diaphragm, which is domed upwards in retirement, flattens out when breathing is forced, pushes the abdominal organs downwards and arches the abdominal wall outwards. This also enlarges the chest cavity. Since the lungs are firmly attached to the inside of the chest wall, they must also expand as the chest space expands. As a result, outside air is increasingly drawn in via the windpipe and bronchi.

Muscle tension is not necessary when exhaling - it is done passively: the diaphragm relaxes and, due to its inherent elasticity, takes on the domed shape again. This shrinks the chest and thus the lungs so that the air inside flows out. You can also consciously exhale forcefully (forced exhalation). The abdominal muscles are used to push the abdominal viscera upwards and thus to push the diaphragm upwards.