Download nervous system

NERVOUS SYSTEM=
The nervous system is the control a
communication system of the body.
main job is to send and receive message
The nervous system allows people
interact with the world around them. T
brain, spinal cord, and nerves make up t
nervous system. The cells that make
the nervous system are called neuron
These long, stringy neurons are perfect f
carrying the electrical messages that a
the “language” of the system. In betwe
neurons there are tiny gaps. There a
three kinds of neurons:
1. Sensory neurons-passes informati
on
2. Motor
neurons-responsible
sending messages to the muscles a
glands
3. Connecting neurons relay messag
between the sensory and mot
neurons
The brain is made up of the cerebrum, t
cerebellum and the brain stem. The tw
halves, or hemispheres, of the cerebru
make up the largest part of the brain a
control the senses, motor activity, and o
ability to learn and reason.
The rig
hemisphere controls the left side of t
body while the left hemisphere controls t
right side. The cerebrum is composed
white cells covered with an outer layer
gray matter called the cortex. The gr
matter is in folds or convolutions giving
grater surface area.
The brain stem is like a flower stem. T
stem of a flower carries nutrients from t
roots to the leaves and petals. The stem
the brain is composed of nerve tiss
carrying information from the cerebrum a
spinal cord.
The brain stem handl
functions that do not require conscio
thought or action such as circulation a
respiration or hunger and thirst. The bra
stem is the oldest part of the brain a
controls emotions like fear and anger.
The spinal cord is like a long
extension of the brain stem. The
cord is around 18" long in an adult
and 3/4" thick. Thirty-one pair of
spinal nerves branch out from the
spinal cord and are called the
peripheral nervous system.
There are approximately 45 miles
of nerves that send impulses as
rapidly as 325 miles per second.