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The Body Electric
to send the impulse all the way to the brain for instructions. Still other
fibers connect spinal neurons with those in the brain, and in the brain
itself the interconnections reach such a density that each nerve cell may
hook up with as many as twenty-five thousand others.
Except for a few specialized components like the naked fiber tips that
enter into neuroepidermal junctions, all parts of every neuron are swad-
dled in various types of perineural cells. In the brain there are several
kinds, collectively called the glia, in which the neurons are embedded
like hairy raisins in a pudding. The cell bodies in the cord also are
surrounded by glial cells, but their axons and dendrites,
which include