thesis
Control mechanisms of cell proliferation in intestinal epithelium
- Publication date
- 12 January 1977
- Publisher
- In the adult organism some organs and tissues still
contain proliferating and differentiating cells, whereas
other organs only consist of non-dividing specialized
cells. On the basis of their proliferative activity cell
populations may be classified into three categories (135,
138,208). In some cell populations, e.g. neurons, no cell
divisions occur in the adult organism, and these have been
referred to as "static" or "stable" cell populations. In
other cell populations the number of cells keeps increasing
in the adult organism at a slow rate with scattered mitoses,
e.g. parenchymal cells of liver and kidney; such cell populations
are called "growing" or 11 expanding" cell populations.
In some organ systems cell proliferation occurs at a
high rate in the adult organism, and mitotic figures are
abundant. These cell populations do not increase in size,
or only to a slight degree, and cell production is balanced
by continuous cell loss. These cell populations are called
"renewing" cell populations (141). Examples of 11 cell renewing
systems" are epidermis and derivatives, gastrointestinal
epithelia, testis and blood-forming tissues. The size
and the functional capacity of such a cell population is
dependent on the precise bqlance between cell production
and cell loss, while some flexibility is needed to meet
with possible perturbations of the system.