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Take a breath - what happens when breathing?
Posted on
29.11.2024
Edited on
2.12.2024
Contents
Breathe in. Breathe out. Often little attention is paid to breathing because it happens naturally without having to be consciously and actively controlled. Yet breathing is a vital process that requires muscles as well as the lungs and is controlled by the brain.
Breathing often only becomes conscious when breathing difficulties occur.
This article explains what happens in the body when we breathe and thus creates the basis for shedding light on breathing problems that can occur with Long Covid, for example.
The path of air
Air enters the body through the mouth or nose. In the nasopharynx, the air is adjusted to the body temperature and humidified. The air then enters the lungs via the trachea.
The lungs are the central respiratory organ. It consists of two lung wings. The left lung is usually slightly smaller, as the heart on the left side of the chest also needs space.
Each lung wing is criss-crossed by a widely branched network of tubes. These tubes are the bronchi. The bronchi are widest at the entrance to the lungs. The further they penetrate into the lung, the more branched and smaller they become. Visualised, they resemble a branch that continues to branch out.
At the end of these ‘branches’ are the alveoli (air sacs). A person has around 300,000,000 alveoli. A single alveolus has a diameter of around 0.2 mm. Together, however, they have a surface area of over 100 square metres. Oxygen is extracted from the air we breathe via this surface area of the alveoli.
The bronchi therefore transport the air we breathe to the alveoli. The alveoli filter the oxygen (O2) from the air.
This oxygen enters the blood and is transported to the organs and tissues via the cardiovascular system. This is because all body cells need oxygen in order to function.
When breathing out, carbon dioxide (CO2) is disposed of as a waste product in the body.
Carbon dioxide is transported to the alveoli in the lungs via the blood. Here the carbon dioxide passes from the blood into the alveoli and is then exhaled through the bronchi, windpipe, nose or mouth.
Breathing
Breathing occurs without doing much. When holding breath, sooner or later the inevitable urge to gasp for air occurs.
This is because breathing is controlled by the respiratory centre in the brain. This respiratory centre is located in the brain stem. The brain stem is a part of the brain that controls essential vital functions such as heart rate, blood pressure and breathing.
The carbon dioxide content in the blood is measured via special receptors. This information is transmitted to the brain, which in turn regulates breathing and respiratory rate. In this way, both the supply of oxygen to the body and the purification of carbon dioxide are controlled.
The brain controls breathing without the need for active conscious control. To trigger a breath, signals are sent from the brain via the autonomic (vegetative) nervous system to the respiratory muscles and the auxiliary respiratory muscles.
The main motor for breathing is the diaphragm. The diaphragm is a muscle-tendon plate that separates the chest cavity from the abdominal cavity.
When inhaling, the diaphragm contracts. Together with the rib muscles, it expands the lungs and air flows in.
In addition to the diaphragm and the rib muscles, several other muscles are involved in breathing. However, which muscles work together depends on the type of breathing. Examples of breathing are chest and abdominal breathing.
During normal breathing, the muscles are only required during inhalation. It ensures that a negative pressure is created, which leads to air being sucked in. During normal exhalation, the muscles involved relax. Elastic support fibres in the lungs contract and the surface tension of the alveoli increases. This forces air out of the lungs.
Breathing is a complex process in which various organs and structures are involved. It ensures the vital supply of oxygen to the body and the removal of carbon dioxide.
When inhaling, the diaphragm lowers and the intercostal muscles raise the chest. This creates a negative pressure that draws air into the lungs. Exhaling is usually a passive process in which the muscles relax and the lungs contract.
An adult breathes about 12-15 times per minute at rest. An adult breathes in and out around 20,000 times a day.
Breathing is controlled by the respiratory centre in the brain. Special receptors measure the carbon dioxide content in the blood and regulate the breathing rate accordingly.
[1] Loscalzo, J., Fauci, A.S., Kasper, D.L., Hauser, S.L., Longo, D.L., & Jameson, J.L. (2022). Harrison's Principles of Internal Medicine (21st ed.). McGraw-Hill Education.
[2] Pape, H.-C., Kurtz, A., Silbernagl (2023): Physiology. jumpers
[3] Iberl, G. (2017.). Nursing expertise: pneumology. Jumper.
[4] Krögel, C., & Costabel, U. (eds.). (2014). Clinical pneumology: The reference work for clinics and practices. Thieme.
Types and possible causes of breathing difficulties
A feeling of not getting enough air, a feeling of tightness, or unusual breathing sounds: Breathing difficulties include any difficulty that can occur when breathing.
Respiratory problems with Long Covid
Persistent cough, shortness of breath, tightness or pressure in the chest, shortness of breath in stressful situations: Breathing problems are a common symptom of long Covid. This applies equally to mild and severe disease courses, although possible causes differ
Breathing exercises: Relieve breathlessness and strengthen t
Breathing exercises can help relieve acute shortness of breath. Performed regularly, they can also be a valuable tool for strengthening the lungs.
