Author : Hanny Indrat Wahyuni

Summary : The word growth can be applied to a cell, an organ, a tissue, an individual animal or a population. During the growth of an animal, the cells increase in number and size while the extra-cellular substances accumulate. Growth could be difined as a change in size, and measured in terms of length, volume or mass (Hafez, 1969). The growth of body cells can be divided into renewing, expanding, and static populations. In renewing population, cells are constantly lost or destroyed and then replenished by the proliferation of stem cells restricted to a generative zone. In expanding populations, cells grow by diffuse proliferation. This process ceases once the adult size of the organ is attained. On the otherhand, static populations growth is by cellular hypertrophy, except during the early development stages (Hafez, 1969).