Hypertrophy

Hypertrophy (Gr. 'over-nourishment') is the term applied in medicine to the enlargement of certain organs of the body. The best examples of this change are seen in the muscular system, where it may occur altogether independently of disease. The huge bosses of flesh that stand prominently forward in the arm of a blacksmith or of a pugilist, and in the leg of an opera-dancer, are illustrations of hypertrophy where the general health may be perfect. In double organs, such as the kidneys and lungs, if the organ on one side degenerates through disease, the organ on the opposite side is often found to enlarge and carry on double work. In these cases hypertrophy is an effect of disease, but is at the same time a resource of nature to preserve life. There are, however, cases in which the hypertrophy has a hurtful instead of a conservative effect, as, for example, hypertrophy of the thyroid gland, constituting the disease known as goitre or bronchocele, hypertrophy of the prostate gland, of the spleen, &c. The following are, according to Paget, the conditions which give rise to hypertrophy: (1) The increased exercise of a part in its healthy function; (2) an increased accumulation in the blood of the particular materials which a part appropriates in its nutrition or in secretion; (3) an increased afflux of healthy blood. In hypertrophy of the muscular tissue the first and third of these conditions are present. In hypertrophy of the fatty tissue, constituting obesity, there is an excess of fat or of its chief elements in the blood.