The capillary is the smallest human blood vessel and contributes to the so-called microcirculation. The thickness of its inner wall layer is only one cell.
These microvessels have a diameter of 5 - 10 μm and connect arteries with veins and provide for the exchange of water, oxygen, carbon dioxide and many other nutrients and chemical waste products between the blood and the tissues surrounding it. During embryonic development, new capillaries are created by vasculogenesis, a process of blood vessel formation within which new endothelial cells are formed and expanded into vascular channels.
The term angiogenesis in turn refers to the formation of new capillaries by secreting or cleavage processes from already preformed blood vessels.
Blood flows through arteries away from the heart. These branch and constrict further to arterioles and in a further step to capillaries.
After the blood has passed through this stage, it flows from the capillaries through the dilated venules to the veins and back to the heart. Capillaries do not work on their own. The capillary bed is an intertwined network of capillaries that feed a single organ. The greater the metabolism of organ cells, the more capillaries are needed to provide nutrients and dispose of waste products.
The capillary bed can consist of two different vessels: the true capillaries, which are responsible for the actual exchange between cells and the circulation. In addition, there is the vascular shunt in the capillary bed, a short vessel that connects a venule directly to an arteriole.
In one sense, capillaries function as a form of communication between arteries and veins. But they are also small blood vessels, carry blood and supply the various organs.
A network of capillaries, which is responsible for the supply of individual organs, is called capillary bed. Of these, countless exist in the human body. They supply the organs with amino acids, proteins and most importantly: with oxygen. Without which the organs could neither fulfill their tasks nor survive. In addition to functioning as a provider of essential nutrients through the blood, the capillaries act as disposers of byproducts of organic production.
This waste is taken up by them and forwarded to leave the body. The amount of capillaries in the human body is impressive. If you could put together the length of all capillaries in the body of a human adult, you would come to a length of 40, 000 kilometers. Capillaries and their contribution to the metabolism are essential for the health and existence of the human organism.
A conspicuous but rather cosmetic complaint associated with the capillaries is redness in the skin that results when capillaries are injured. Redness in the face is very well known, usually on the cheeks or nose.
This is usually done by too fast narrowing and / or dilation of the vessels, which eventually leads to fractures in the vessel walls. Thin and sensitive skin is particularly susceptible to these reactions. External circumstances that can be avoided to curb these symptoms are: hot environment; strong wind in the face; long, intense sunlight; rapid temperature change; Squeezing and squeezing the skin.
Certain birthmarks are also due to such discoloration under the skin. There is no health risk. But if the redness is found on conspicuous body parts, they can be treated with a laser therapy.
Among the more serious diseases affecting the capillaries is the capillary leak syndrome. By far inexplicable changes in the walls of the capillaries occurs suddenly increased blood plasma and penetrates into the surrounding muscle tissue or other body cavities.
Failure to treat these effects will result in a sharp drop in blood pressure, followed by organ failure and death. The capillary leak syndrome is a very rare disease. Until 2002, only about 60 cases were documented.