Unformatted text preview: th half the DNA content). Many tissues/organs have a very slowly
dividing population of cells called stem cells.
They produce cells that either become more
stem cells or change into progenitor cells or
“transit amplifying cells” which are committed
to differentiate as some specialized type of cell.
Many such fully differentiated cells can no longer
divide and are said to be terminally differentiated
but completely functional. ex: RBC. has lost its nucleus! can't ever
Most terminally differentiated cells gradually
become senescent and are replaced during a
lifetime; a few last an entire lifetime. Fig. 3-17 Terms describing various cell fates:
Proliferating – state of a continuously cycling cell population
seen best in stem cells and their progeny committed to
differentiate: transit amplifying cells
Quiescence – state of cells in G0 but capable of cycling again
Differentiated – state of functionally specialized quiescent
cells, which are stable but capable of dividing again
Terminally differentiated – state of specialized cells that
cannot re-enter cell cycle and divide
Senescent – state of a functional cell no longer able to divide
and losing function
Apoptosis – cell su...
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