How old are the cells in my body?

Janet Duerr Janet-Duerr at
Tue Mar 19 09:29:35 EST 2002

I do not know the accuracy any of the numbers I have seen quoted.  But I
have seen both 1 (US) trillion (1,000,000,000,000) and 100 (US) billion
(100,000,000,000) quoted in news summaries in Science magazine as the
approximate number of neurons in a human.  Just doing a quick perusal on
the web, I found on <> an estimate of 200 (US) billion
(200,000,000,000) neurons for the spinal cord alone.  I also found a
guess of 500,000,000,000 (500 (US) billion) blood cells and 10e14 (100
US trillion) total cells in a human (on both the madsci and the HHMI web
sites) or 10 US trillion cells in a human (on a couple other sites).
Take your pick.


"Gordon D. Pusch" wrote:
> Janet Duerr <Janet-Duerr at> writes:
> > I have read estimates of 1 _trillion_ neurons in the human brain.  So
> > the number must be many times more than that for the entire body.
> You had better go back and check that reference --- 1e10 neurons
> (10 billion in the US, 10,000 million in the UK) is closer to reality.
> (Perhaps you or your reference have confused US billion (1e9) with
> UK billion (1e12) ???)
> -- Gordon D. Pusch
> perl -e '$_ = "gdpusch\\n"; s/NO\.//; s/SPAM\.//; print;'

More information about the Cellbiol mailing list