Name: Wildman Jackson
Location: N/A
Country: N/A
Date: N/A
Question:
I have heard that approximately 1 million brain cells die every day. Is
this number correct? I have also heard that there is enough brain cells to last the
average human about 120 years. Is the actual number of brain cells known approximately
(or how long they will last)?
I'm just trying to pace myself here.... :)
Replies:
You have heard wrong. Certainly, not that many die daily. We believe that
humans have about 100 billion nerve cells (and ten to fifty times more of supporting
cells in the brain with them!). We are born with more than that, but many die during
our first year of life. We are unsure of whether there is significant change in that
number over later life. There is a shrinking of brain mass in old age. But cell numbers
stay about the same, as far as is known. This would be a good project for an
enterprising young scientist like yourself! When brains change in function, it is not
usually due to losing or gaining cells. It is usually due to changes in connections
between cells. These are called synapses. Each brain cell in a human brain receives
input from 1000s of other cells, and each of these 1000 cells can put 100s of synapses
on that 1 cell that it is communicating with. Each cell therefore can have tens of
thousands of synapses. It is the weakening and strengthening of these synapses throughout
the brain, that changes how the brain functions for the most part. That is our working
theory. But the brain is the most complicated object yet encountered (more cells in it
that stars in the galaxy!). It will yield more interesting data yet!
NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.
