It’s estimated that there are approximately 60,000 miles of blood vessels in the adult body. These blood vessels include arteries, veins, and capillaries. They are all protected by a microscopic inner lining of endothelial cells, which are commonly called the endothelium. It’s important to note that these cells line the entire circulatory system from the inside of your heart all the way down to your smallest capillary. When added up, the volume of these endothelial cells would cover the surface area of 4 to 8 tennis courts depending upon the size of the individual. The endothelium is only one cell thick and can’t be seen by the human eye.
Once discovered, the endothelium was classified as an inert membrane whose primary function was to keep the blood in the circulatory system and out of the body’s tissues and organs. Research over the last 25 years has shown that your endothelium is an active, multi-functional organ that plays a vital role in metabolic, immunologic, and cardiovascular health. Your endothelium is now considered to be the single largest secreting organ in the body.
Endothelial health is so important that the 1998 Nobel Prize in Medicine was awarded to three American researchers who discovered how the endothelium converts the amino acid L-arginine into nitric oxide – the master signaling molecule of your entire cardiovascular system.
Because endothelial cells line every blood vessel they play an important role in the proper function of every organ in your body. The following is a list of the known functions of the endothelium. Each function plays an important role in endothelial health, cardiovascular health, and your overall wellness: