Scars are areas of fibrous tissue (fibrosis) that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound (e.g. after accident, disease, or surgery) results in some degree of scarring. An exception to this is animals with regeneration, which do not form scars and the tissue will grow back exactly as before.
Scar tissue is the same protein (collagen) as the tissue that it replaces, but the fiber composition of the protein is different; instead of a random basketweave formation of the collagen fibers found in normal tissue, in fibrosis the collagen cross-links and forms a pronounced alignment in a single direction. This collagen scar tissue alignment is usually of inferior functional quality to the normal collagen randomised alignment. For example, scars in the skin are less resistant to ultraviolet radiation, and sweat glands and hair follicles do not grow back within scar tissue. A myocardial infarction, commonly known as a heart attack, causes scar formation in the heart muscle, which leads to loss of muscular power and possibly heart failure. However, there are some tissues (e.g. bone) that can heal without any structural or functional deterioration.
Famous quotes containing the word scar:
“Nothing is uglier than the sinner, nothing so leprous or fetid; the scar of his crimes is still raw, and he stinks like the cave of Hell.”
—Aurelius Clemens Prudentius (c. 348405)
“One hand stiffheaviness of forties & menopause reduced
by one heart stroke, lame nowwrinklesa scar on
her head, the lobotomyruin, the hand dipping downwards to
—Allen Ginsberg (b. 1926)
“I could see the thing
with its black head
but there wasnt a tear left
and the scar of my wound
—Hilda Doolittle (18861961)