The endothelium is the thin layer of the cells which lines the interior surface of the blood vessels. This forms the interface between the circulating blood in the lumen and the rest of the vessel wall. Endothelial cell line the entire circulatory system from the cell to the smallest capillary. These cells reduce the turbulence and hence lead to the pumping of the blood to much further distance.
The endothelial tissue is the specialized type of the epithelium tissue which is one of the four types of biological tissue in the animals. More specifically it is a simple squamous epithelium.
The foundational model of the anatomy makes the distinction between the endothelial cells and the epithelial cells on the basis of which the tissues can develop from and states that the presence of the vimentin rather than the keratin filaments separate them from the epithelial cells.
Endotheliums of the interior surface of the heart chamber are called the Endocardium. Both blood and the lymphatic capillaries are composed of the single layer of the endothelial cells called the monolayer.
- Endothelial cells may be involved in many aspects of the vascular biology. Some of the functions are as follows:
- Vasoconstriction and vasodilation, and hence the control of blood pressure.
- Blood clotting (thrombosis and fibrinolysis).
- Formation of new blood vessels (angiogenesis).
- Barrier function – the endothelium acts as a selective barrier between the vessel lumen and surrounding tissue, controlling the passage of materials and the transit of white blood cells into and out of the bloodstream. Excessive or prolonged increases in permeability of the endothelial monolayer, as in cases of chronic inflammation, may lead to tissue oedema/swelling.
In some organs, there are highly differentiated endothelial cells to perform specialized ‘filtering’ functions. Examples of such unique endothelial structures include the renal glomerulus and the blood-brain barrier.
The role of Endothelium
I do feel that you must have an idea about the cholesterol. The cholesterol really leads to the blood pressure. There is a certain increase in the blood pressure if the cholesterol is increased in the blood vessel. I really feel that the endothelium can do a lot in controlling the heart disease. It is really a very important part of the blood vessel.
Scientists have recently discovered that when people digest fat then cholesterol is carried in the blood. This sometimes increases the blood pressure because the cholesterol forms a layer above the interior wall of the blood vessels. As a result the blood does not move smoothly through the blood vessels which may lead to heart diseases.