Page 177 - The Miracle of Hormones

Communication in Nerve Cells

the cell. Most frequently, the function of the single axon is to transmit the
message received from the body of the cell through the terminals and
extensions.
At this point, we must point out the special design of axons. A spe-
cial covering layer called "myelin sheath" encloses an axon. Nerve im-
pulses are propagated at specific points along the myelin sheath; these
points are called "the nodes of Ranvier." Research has shown that signals

jumping from node to node travel hundreds of times faster than signals
traveling along the surface of the axon. The sheath and "nodes" on the
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axon make it possible for the signal to be transmitted in the most suitable
and rapid manner.
Neurons establish communication in our bodies by a unique meth-
od that comprises extraordinarily complex electrical and chemical opera-
tions, ensuring flawless coordination both in the brain and between the
brain and other organs. When you complete a simple action, such as
holding this book in your hands, flipping its pages or running your eye

through its sentences, there is a very dense communication traffic in the
nerve cells deep within your body. Examining closely the neurons that
establish this extraordinary communication network will help us to
understand better what an important wonder of creation they are.

Soma
Nucleus
Schwann
cell
Synapse

Axon hillock

Axon

Mitochondria
Dendrite
Nucleolus
CROSS SECTION OF A MOTOR NERVE CELL
Nissl body