Hypertrophy

Hypertrophy is the increase of the size of an organ. It should be distinguished from hyperplasia which occurs due to cell division; hypertrophy occurs due to an increase in cell size rather than division. It is most commonly seen in muscle that has been actively stimulated, the most well-known method being exercise.

Hypertrophy can be pathological in many organs; for example in the heart hypertrophy of the left ventricle can be associated with up to a four fold risk of dying over the following 5 years. In skeletal muscle, it is usually helpful and increases strength.