Atrophy

Atrophy (Gr. a, 'not,' and trophē, 'nourishment'), an alteration of the vital processes in a living organism, either animal or vegetable, resulting in a diminution in size and functional activity of the whole organism (general atrophy), or of certain of its organs or tissues. It may be a natural process, as in atrophy of the thymus gland during childhood, or in general atrophy of old age; but is much more commonly the result of disease or injury. It may be caused (1) by a deficient supply of nourishment, as by starvation and diseases affecting digestion, or by injury of or pressure on the arteries supplying a part with blood, as when beggars produce atrophy of their muscles by tight bandaging of their limbs; (2) by excessive waste of tissue, as in fevers; (3) by diminished functional activity, as in atrophy of paralysed limbs from disease; and (4) by certain poisons, such as iodine, lead. Compare HYPER-TROPHY, NUTRITION.