The Nervous System

The Human NervousThe Human Nervous
System 35-2System 35-2
Name the three parts of a neuron.Name the three parts of a neuron.
Describe the way in which a nerveDescribe the way in which a nerve
impulse occurs.impulse occurs.

Can you label a neuron?Can you label a neuron?
• Cell body
• Nucleus
• Dendrites
• Axon
• Node of Ranvier
• Nucleus - Schwann cell
• Schwann cell
• Myelin sheath
• Synaptic knob
• Terminal Branches

Three types of Nerve Cells
• Sensory Neurons
• Inter Neurons
• Motor Neurons

A system that controls all of the
activities of the body.
The nervous system is made of:
The brain The spinal cord
The nerves The senses

The nervous system also allows you to
react to a stimulus.
A stimulus is a change in the environment.
Example: A hot stove
Or… tripping over a rock

Your reactions are automatic.
Automatic means that you do not
have to think about your reactions.
Example: If a bug flies by your eye,
you will blink.

An organ that controls your
emotions, your thoughts, and every
movement you make.

The Central Nervous System is made
of the brain and the spinal cord.
The Central Nervous System controls
everything in the body.

The Outer Nervous System is made of
the nerves and the sense organs.
Nerves Sense organs

Messages carried throughout the body
by nerves.

You have a nerve along your whole arm.
The “funny bone” is the only place on
the arm where the nerve is not
protected.
The “funny bone” is on the elbow.

* The Central Nervous System controls
all of the body’s activities.
* The Central Nervous System is
made of two main organs.
1. The brain
2. The spinal cord

* The spinal cord sends messages to the
brain.
* The spinal cord is the part of the
nervous system that connects the brain
to the rest of the nervous system.

* The brain controls everything in the
body.
* The brain is made of more than 10
billion nerves!
* The brain is divided into three
parts and is protected by the skull.

* The Brain has three main parts…
1. The Cerebrum
2. The Cerebellum
3. The Brain Stem

* The Cerebrum is the largest part of
the brain.
1. The cerebrum controls your thinking.
2. The cerebrum controls your memory.
3. The cerebrum controls your speaking.
4. The cerebrum controls your movement and identifies
the information gathered by your sense organs.

* The cerebellum is below and to the
back of the cerebrum.
1. The cerebellum controls you balance.
2. The cerebellum controls your posture.

* The Brain Stem connects the brain to
the spinal cord.
* The nerves in the brain stem control
your heartbeat, breathing, and blood
pressure.

* The vertebrae are the many
bones that protect the nerves in
the spinal cord.

* The Outer Nervous System’s job
is to connect the Central Nervous
System to the rest of the body.
* The outer nervous system carries
messages between the central nervous
system and the rest of the body.

* The outer nervous system is made of
the nerves and the sense organs.
Ear
Eye
Skin
Nerves
Tongue

* An automatic reaction that
happens without thinking about it.
* A reflex happens quickly in
less than a second.

* The outer nervous system
controls the body’s activities
that you don’t think about.
* The outer nervous system controls
activities in your small intestine, your
breathing, and your heartbeat.
controls

Sense organs
carry messages
about the
environment to
the central
nervous
system.

The eyes, ears, nose, tongue, and
skin are examples of sense organs.
The sense organs gather
information (light, sound, heat,
and pressure) from the
environment.

The environment is everything
outside the body.
The sense organs gather
information from outside the
body, then send the messages to
the brain.

Vision is your ability to see.
Vision involves the eye and the brain.

The eye is one of your sense organs.
The eye is made of the iris
and the pupil.
The eye gathers pictures and
sends them to the brain.

The colored part of the
eye is the iris.
The black part of the
eye is the pupil.
The pupil becomes
larger and smaller as
it controls the light
coming into the eye.
IrisPupil

When a sound is made, the air
around the sound vibrates.
Hearing starts when some of the
sound waves go into the ear.

There are nine main parts of the ear.
1. Pinna
2. Ear canal
3. Ear drum
5. Anvil
6. Stirrup
7. Cochlea
4. Hammer 8. Eustachian tube
9. Auditory nerve

The ear canal is the tube between the
outside of the ear and the ear drum.
The ear drum is in the middle ear. It
vibrates when sound waves hit it.
The pinna is the part of the ear
that you can see.

The three smallest bones in the body, the
hammer, the anvil, and the stirrup,
are in the middle ear.
The hammer gets the vibrations from the
eardrum, then sends them to the anvil.
The anvil passes the vibrations to the stirrup.
The stirrup passes the vibrations
to the inner ear.

The inner ear is made of
the cochlea and liquid.
The cochlea is in the inner ear. The
cochlea looks like a shell.
The Eustachian tube controls the amount
of pressure in the ear.
The auditory nerve carries the
hearing information to the brain and
the brain tells us what we heard.

The ear works with the brain to
control your balance.
All of your movements are controlled
by balance and muscles.
The liquid in your inner ear is responsible
for your balance.
The liquid in your ear moves when we move.
The liquid movement sends information to the
brain to tell it how we are moving.

The sense of touch is located in the skin.
The nerves in the skin allow us
to feel texture, pressure,
heat, cold, and pain.
Texture is how something feels.

The nose controls your sense of smell.
The nose is able to smell 80
different kinds of smells.

Your sense of taste comes from the
taste buds in the tongue.
Taste buds are the parts on the tongue
that allow us to taste.
The four kinds of taste buds are
sweet, sour, bitter, and salty.

Tastes and smells work
together to make flavors.
Flavors are the tastes
of food and drinks.

The Nervous System

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