The pulmonary circulation
The pulmonary circulation is also called the small body circulation. Its main function is to enrich the blood with oxygen (O2) and release harmful carbon dioxide (CO2). Pulmonary circulation begins in the right atrium of the heart (atrium dextrum), which leads via the tricuspid valve (valva atrioventricularis dextra) to the right ventricle (ventriculus dexter).
The venous blood, which comes from the periphery of the body, is pumped through the pulmonary arteries (arteria pulmonalis) into the two lungs. In the capillaries, gas exchange takes place by enriching the blood with oxygen (O2) and simultaneously releasing carbon dioxide (CO2). Via four pulmonary veins (Venae pulmonales), the arterial blood is then transported to the left atrium, from where it enters the left main chamber. This is followed by the large body circulation, which supplies the entire body with oxygen-rich blood.
What is the difference between the large and small cycle?
The small and the large body circulation both transport blood within our body, but have different functions. The large body circulation starts in the left ventricle (Ventriculus sinister). Via the aorta, arterial blood enriched with oxygen (O2) is pumped into the body.
This blood supplies the most diverse areas, such as our organs, our brain and also all muscles. For this reason there is a high pressure (approx. 120mmHg) in the major circulation of the body, as the blood has to travel a long distance.
The used venous blood now contains only little oxygen and instead a lot of carbon dioxide (CO2). Via the upper and lower vena cava (superior/inferior vena cava) it is returned to the right heart, where the small circulation (also called pulmonary circulation) follows. Starting from the right atrium (atrium dexter) via the right ventricle (ventriculus dexter), the blood reaches the lungs, where gas exchange takes place.
Here, carbon dioxide is released and oxygen is absorbed, so that arterial blood is returned to the left heart via the pulmonary veins. From here, the great circulation of the body begins anew. The pulmonary circulation is not about supplying the tissue with oxygen, but purely about gas exchange, so that low pressures (approx. 15mmHg) are sufficient here.
