CELL GROWTH: Two types of cellular growth occur in body. The individual cells have the capacity to grow by multiplication in their number. They do this by acquiring various substances from the blood and converting them into appropriate cellular elements. This type of growth is hyperplasia.
Sometimes, a tissue such as muscle tissue will increase in mass without an increase in the number of units. This condition is called hypertrophy. This increase in size owe to synthesis and deposition of structural proteins and lipids in the cell.
"It is not a simple life to be a single cell, although I have no right to say so, having been a single cell so long ago myself that I have no memory at all of that stage of my life." —Lewis Thomas (1913–1993) author, biologist, physician.