Collagen, << KOL uh juhn, >> is a protein found throughout the bodies of human beings and animals. Collagen provides strength and gives shape to connective tissues, such as ligaments and tendons, and to bones. It also provides much of the strength and flexibility in skin and blood vessels.
There are many kinds of collagens in the body. All of them are made by cells and secreted into the intercellular substance (material outside the cells). Single collagen molecules can come together and form larger structures, a process important in the formation of tissues.
Collagen may be damaged by injuries, such as cuts and broken bones. A major part of the process by which wounds heal involves the removal of damaged collagen, the formation of new collagen, and the shaping of this new collagen into a tissue. Many of the problems of arthritis are caused by damage to the collagen in cartilage and bone. In certain inherited disorders, collagen is abnormal. Patients with these disorders may have fragile, rubberlike skin and very loose joints. In other diseases of collagen, the bones are easily broken or the skin blistered by minor injury.
Animal collagen has many uses. Gelatin is made from collagen and is used in foods and glues. Collagen is used in shampoos and other cosmetics. In medicine, collagen is used to make artificial heart valves and to repair scars and wrinkles.
