ABSTRACT
This chapter is concerned with the mechanisms influencing growth of cells. It describes the growth and development of major tissue types and organ systems: bone, muscle, and adipose tissue. Two fundamental components are the increase in cell number, or proliferation, and the increase in size of individual cells. The proliferation, or multiplication, of cells is technically described as hyperplasia. The antonym is hypoplasia, and cessation of proliferation is aplasia. Increased size, irrespective of proliferation, is called hypertrophy; the antonym is atrophy, or regression. The control of mitosis is really the control of cellular events during first gap phase when the daughter cell is either made competent to progress to the synthetic phase to begin DNA synthesis or is committed to differentiation. Its activity during the synthetic phase is highly anabolic, with DNA and protein being synthesized and organelle growth taking place. In second gap phase it is metabolically active, although anabolic and catabolic events are probably essentially in balance.
