|Hi, I have been doing a project about what would
happen if you switch one species brain to a
different, example (human to frog), and what part
of the body makes you grow?|
No one really knows because switching a brain is
not possible, at least not now. The brain is
connected to the rest of the body by a very large
number of nerve cells (neurons). It's easy to cut
these, but re-attaching them is not easy. It may
never be possible. You would have to attach one
cut end of a cell to the cut end of a cell from a
different animal. And it would have to be the
right cell. The cells would then have to join up
and heal together.
The other part of your question is a little
easier to answer. The pituitary gland is
about the size of a pea and hangs off the bottom
of the brain. It makes a hormone that tells
certain parts of your body to grow. The cells in
these places divide faster. The pituitary gland
is also controlled by another gland, called the
hypothalamus. Hormones from the pituitary
go into the blood and travel all over the body.
Not every cell responds to the hormone, only the
cells with receptors for the hormone.
Why would it be important for all parts of the
body to get the signal to grow at the same time?
Thanks for asking,
The animal would die.
Organs of an animal are integrated into the body
of that animal. Your brain could not be removed
from your body without killing you, and it
couldn't be put into someone else's body, even
another human, without killing them, too. There
are some organs that can be moved between
individuals of the same species, hence the field
of organ transplants, but it definitely would not
work between species. It might one day be possible
I suppose to swap the brains of two humans, but if
you did that you would create two new
personalities, since brain and body work together.
Between species, if the organ being moved was not
vital, it just wouldn't work, and if it was vital,
then the outcome would be death.
Growth is done by stem cells, cells with the
ability to become multiple different kinds of
cells, and is further regulated by hormones, and
the activity of certain genes. This is a complex
It is nearly impossible to transfer brains
between species because the correct neuron
connections aren't there. Same as if you would try
to plug a guitar into a telephone. Many different
things must come together correctly for the body
to grow--growth hormones from the brain are an
important part of this. But, the adult brain no
longer releases hormones for limb growth (if you
lose an arm it won't re-grow). So the short answer
is if you place the brain of one species in the
body of another, both species will die. We don't
yet have the technology to correctly hook up the
brain even within a single species.
One neurosurgeon successfully transplanted one
dog's brain into another's body, but as it
couldn't be hooked up correctly, it didn't control
any body functions, but the brain itself lived. I
had no idea that this had been done.
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