PROLIFERATION
Proliferation (from Lat. Proles - "offspring" and fero - "I carry") is increasing of cell number by mitosis, causing growth of the tissue. Intensity of proliferation is controlled by stimulating and inhibitive factors, which can be produced either far from the reacting cells (for example, by hormones), or inside them. In the early embryogenesis proliferation goes on constantly. As far as differentiation proceeds, periods of time between cell divisions grow longer. Some differentiated cells, like, for example, nervous cells, are not capable of proliferation.