Page 37 - How It Works - Book of Amazing Answers To Curious Questions, 12

Science*------------------Q�

What does Axon Whyisthefunny
The neural fibre that carries
electrical signals representing motor bone not at all ji1nny?
a nerv commands and sensory information.
look like Myelin sheath ost of the larger nerves in your body are
Fatty insulation that keeps M insulated by muscle, bones and tissue.
axons from short-circuiting. The big exception is the ulnar nerve, which runs
Nerve fascicle down your arm, by way of your elbow. The
A bundle of axons. • Blood vessels nerve carries motor commands to your ring and
Supply of blood that provides pinkie fingers and relays sensory information
neurons with energy. back to the central nervous system. If you bang
Perineurium your elbow, the humerus bone bumps the
Sheath of connective Epineurium nerve, jarring the axons inside, which your brain
tissue that protects Outer connective tissue interprets as a tingling sensation.
each fascicle. that protects the nerve.

What do
nerves do?

Your neurons are fragile cells, and for the most
part can't be replaced if they get damaged. So,
instead of bare axons running through your
body, we have nerves.
A nerve is like an electrical cable, housing
thousands (or millions) of axons in a protective
sheath of tissue. Nerves extend out from your
brain and spinal column, known as the central
nervous system, to the rest of your body.
There are U pairs of nerves extending from
the brain and 31 pairs extending from the
spinal cord. The nerves branch off in your
body, forming a network called the peripheral
nervous system.
The afferent division of the peripheral
nervous system relays signals from
sensory neurons back to the central nervous
system, while the efferent division relays
instructions from the central nervous system
to muscles and glands. Most nerves carry
both types of signals.

ll. Common
peroneal nerve
Connects to muscles in
your lower leg, which lift
your foot.
10. Sciatic nerve
Your longest nerve,
which carries motor
signals to muscles that
bend your leg.

9. Femoral nerve
A key nerve with many
smaller nerve branches
that carry motor
commands to leg
muscles, as well as
sensory information from
the thigh and lower leg.

WorldMags.net How It IM.Jrks 37
WorldMags.net