Download Aim: How does the nervous system function? Do Now

Aim: How does the nervous system
function?
Do Now:
What is a stimulus?
How do your senses work?
Homework: 594-602 #1-5
The Nervous System
How do we respond to stimuli?


Stimulus – Any internal or external change
that causes a response
We come in contact with thousands of
stimuli
External - Noise,
light, smell,
temperature
 Internal – hormones,
or other chemicals
in your body

Nerve Cells

Your nervous system is made up of nerve
cells called NEURONS
Dendrites
Axon Terminal
Axon
Nucleus
Cell Body
Parts of the Neuron


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Dendrite – Receive the impulses from other
neurons and send them to the cell body
Cell Body – Where life processes take place
Nucleus – control center of the cell
Axon – carry impulses away from the cell
body
Axon Terminals – the end of the axons,
sends impulse to other neurons
(Impulse – any message carried by a neuron)
Types of Neurons

Sensory Neurons – receive information and
send impulses to the brain or spinal cord


Interneurons – send messages to motor
neurons


Example: loud noise detected
Example: message sent from brain to motor
neurons
Motor Neurons – send impulses from the
brain or spinal cord to the muscles or glands

Example: sends message to muscles, they
tighten and you jump
Synapses


The area where
neurons send signals
from one cell to
another
It is a gap between the
dendrites of one
neuron and the axon
terminal of another
neuron
Central Nervous System

Brain
Receives information from the spinal cord and
its own nerves
 Processes the information and sends signals to
various parts of the body


Spinal Cord
Brings information from the peripheral nervous
system to the brain
 Sends information from the brain to muscles
and glands

Parts of the Brain



Cerebrum – thinking
takes place here
Cerebellum – Stimuli
Cerebrum
are interpreted,
controls voluntary
muscles, balance
Brain Stem –
Brain
Stem
Controls involuntary
muscles and actions
Cerebellum
Peripheral Nervous System

All nerves and
neurons that branch
away from the brain
and spinal cord
Malfunctions

Polio
Virus that causes full or partial paralysis
 Rare now, a vaccination exists


Meningitis
Inflammation of meninges, or the covering of
the brain
 Treated with antibiotics


Alzheimer’s

Gradual memory loss at a faster pace than
expected with natural aging
ADHD





Attention Deficit Hyperactivity Disorder
(ADHD)
affects an estimated 5% of all boys and 2%
of all girls.
Up to 60% of these children will continue to
have symptoms into adulthood
Over a million children take prescription
medicines to control hyperactive behavior
The cause is not yet known