Download The Nervous System

1. The function of the
nervous system is to:
Receive information
about what is
happening both inside
and outside your body.
2. Stimulus
- a change or signal in the
environment that can make an
organism react.
Response
- What your body does in
reaction to a stimulus.
Homeostasis –
The process in which a living thing
keeps it’s internal state normal
despite it’s external
environment.
3.
Examples: Hunger, Thirst, ?
4. Your brain is an ORGAN and
the nerves running through your
body are tissues.
5. A neuron is a cell that carries
information through your
nervous system.
Neuron Structure
Neuron Structure
6. The message that a neuron
carries is called a nerve impulse.
7. A dendrite carries impulses
towards the cell body.
The axon carries impulses away
from the cell body.
8. 3 types of neurons
1. sensory – picks up stimuli from
the internal or external
environment.
Ex: Hear cell phone ring.
2. interneurons – carries nerve
impulses from one neuron to
another.
Ex: Carries message to brain
3. motor neuron – sends impulse to
muscle or gland, and it reacts.
Ex: Brain sends message to
muscles in hand to pick up the
phone.
Divisions of the Nervous
System
9. Central Nervous System
– consists of the brain
and the spinal cord.
10. Peripheral Nervous
System – consists of all
the nerves located
outside of the brain and
spinal cord.
11. The 3 Main Parts of the Brain
A. Cerebrum – Interprets input
from our senses and carries out
tasks such as learning, thinking,
remembering and making
judgments.
*Largest Part!*

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The cerebrum has 2 halves.
The right half controls the left side of the
body.
The left half controls the right.
The cerebrum gives you your personality,
how you develop it creates who you are.
B.

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Cerebellum - coordinates
the actions of your muscles
and helps maintain your
balance.
The cerebellum is part of
what you train when you
are practicing sports and
music.
The cerebellum is also
what keeps you from
falling down – most of the
time.
C. Brainstem – controls your
involuntary actions such as
breathing and your heartbeat.
 The
brain stem controls the
“fight or flight” response
found in all animals, including
humans.
The fight or flight response is
a life saving response to
perceived danger.
12. The Spinal Cord
The Spinal Cord is the only pathway
between your brain and your
peripheral nerves.
13. Your backbone (vertebrae) protect
your spinal cord.

If you broke your back and severed your
spinal cord you will become paralyzed
because your brain cannot get signals to
your peripheral nerves.
14. The Peripheral Nerves
The Peripheral Nerves are ALL of the
nerves that lie outside of the brain and
the spinal cord.

All the nerves in your hands, feet, and
mouth are controlled by peripheral
nerves. **43 Pairs
Reflex - an automatic response that occurs
very rapidly without conscious control.
Reflexes help to protect the body.
Ex – Move hand away from hot object
Duck if something is thrown at you
Blink if something comes close to your eye
Sneezing to clear airway