capillær

A capillary is a small, narrow tube or vessel through which blood vessels or lymphatic vessels are divided. Capillaries are a crucial part of the circulatory and lymphatic systems in the human body.

In the circulatory system, capillaries are tiny blood vessels that allow the exchange of oxygen, nutrients, and waste products between the bloodstream and cells. Oxygen and nutrients from the blood diffuse out of the capillaries and into the cells, while carbon dioxide and waste products, such as lactic acid, diffuse out of the cells and into the capillaries. This exchange process occurs in the walls of the capillaries, which are thin and permeable.

Capillaries are found in various parts of the body, including the lungs, muscles, kidneys, and liver. In the lungs, capillaries facilitate gas exchange between the inhaled air and the bloodstream. In muscles, capillaries supply oxygen and nutrients to the muscle cells and remove waste products. Capillaries also play a crucial role in the kidneys, where they help to filter waste products from the blood and regulate electrolyte balance.

The structure of a capillary consists of a thin-walled tube with a diameter of approximately 5-10 micrometers. The capillary wall is composed of a single layer of epithelial cells, which allows for the exchange of substances between the blood and tissues. The capillary lumen is the hollow space within the capillary tube, where the flow of blood occurs.

Overall, capillaries are essential for the proper functioning of various bodily systems, including the circulatory and lymphatic systems. Their delicate structure and permeable walls enable the exchange of vital substances between the bloodstream and tissues, supporting the overall health and well-being of the body.