A neuron has an important job to do: relay information to,
within, or from the CNS. Its structure helps it accomplish its
goal. As shown in figure 1, each neuron has a cell body,
dendrites, and an axon. The cell body contains the nucleus and
other organelles. The dendrites are fibers that extend away
from the cell and resemble a tree. They act as receptors
because they receive a stimulus and conduct it to the cell body
to interpret. A neuron’s axon is a single fiber that also extends
from the cell body. It conducts impulses away from the neuron,
either to another neuron, to a muscle, or to a gland. Some
axons are covered by a fatty, insulating material of myelin
sheath (Taylor 150). This myelin sheath is like a blanket that
wraps around the axon. However, the myelin doesn’t cover it
like one big blanket. Instead, the cells that make up the myelin
(called “Schwann cells”) are like multiple small blankets that
leave exposed spaces in between. On an axon, the exposed
spaces are called nodes (also called “nodes of ranvier”).
Impulses jump from node to node, making their transmission
quicker and more precise.
So what happens inside your body when you experience a
reflex after touching a sharp needle? The CNS and PNS work
together to send and perform commands in the body. When we