Biomedical Engineering Reference
In-Depth Information
fig. 2.1. Generalized stem cell biology.
A stem cell divides to produce another
stem cell like itself and a progenitor cell
that goes on to develop into a specialized
cell type.
types of cells in the human body. Ancestral lines for the trillions of cells
in the human body originate in a small group of
pluripotent
(having a plu-
rality of
developmental potentials
) stem cells present in very young embryos
and, ultimately, from the fertilized egg cell itself.
in most cells, mitotic cell division produces two identical daughter cells.
But when a stem cell divides, it produces two kinds of cells: (1) another
cell like itself and (2) a
progenitor cell
committed to producing specialized
cells via subsequent cell divisions (fig. 2.1). The stepwise specialization ac-
companying cell division that produces cells dedicated to specific tasks is
called
cell differentiation.
examples of differentiated cells include oxygen-
carrying red blood cells, electrical signal-conducting nerve cells, contract-
ing muscle cells, and insulin-producing pancreatic cells. Development of
an entire plant or animal from a single fertilized egg, wound healing, and
the daily replacement of worn-out blood and skin cells are examples of
what stem cell division and subsequent cell differentiation can accomplish.
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