Download Neurons and action potential

Neurons and Action
Potential
Objectives
1. Understand the anatomy of a neuron and how
signals travel along neurons.
• Describe parts and function of neuron and build
complete neuron.
2. View the concept “Fire together, wire together”
and graph signal strength.
• Use built neuron to fire to another neuron and
strengthen connection.
3. Visualize the idea of creating an action
potential.
•
Show how neurons need to reach threshold to fire
action potential.
Neurons and Action Potential
Neurons:
• Are cells of the nervous
system
• Process and transmit
information electrically
and chemically
• Produce voltages
• Have a nucleus and
other organelles and are
surrounded by a cell
membrane
If a neuron fires and activates another neuron then the
connection between those neurons is strengthened.
Neurons and Action Potential
•
Dendrites bring information to the cell body and axons
take information away from the cell body.
•
Signals travel down the axon to the terminal branches.
•
A typical synapse is a contact between the axon of one
neuron and a dendrite of another.
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Neurons and Action Potential
•
When you learn, messages travel from one neuron to
another, over and over making connections between
neurons.
•
Information flows from one neuron to another across a
synapse, which is a gap that separates neurons.
•
Neurotransmitters from the presynaptic region flow to
receptors at the postsynaptic region.
Neurons and Action Potential
•
When a neuron is not sending a signal it is at resting
potential.
•
Action potential occurs when a neuron sends info down
an axon.
•
When a neuron receives a message from other neurons,
the neuron is depolarized.
•
The neuron must reach threshold to fire an action
potential.
Neural Tissue Engineering
Neural tissue engineering is a sub-field of tissue
engineering.
Neuronal tissue grafts and scaffolds are implanted to
promote nerve regeneration and to repair nerve damage.
Current Research:
• Spinal cord regeneration
• Inflammation and fibrosis elimination
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Student Activity
Goal:
Build a neuron and create a setup that
will allow neurons to fire to other
neurons.
Student Activity
Materials:
•
Clay
•
LED
•
Copper wire strips
•
Pennies
•
Paper clips
•
Alligator clips
•
Voltmeter
•
Neurotransmitters
Student Activity
Procedure:
1. Create your own neurons using clay, wire and LED.
The wire will act as dendrites and axon branches.
The LED will be placed in the cell body of the neuron
with leads sticking out.
2. Insert a paper clip and penny into a neurotransmitter.
3. Using alligator clips make a connection between two
neurons by sending a neurotransmitter from one
neuron to another.
Student Activity
5. Using the voltmeter measure the voltage. If the LED
is lit threshold has been reached and that neuron can
fire an action potential.
6. Keep adding neurotransmitters and measuring the
voltage. If the LED gets brighter the connection
between the neurons is strengthened.
7. Graph the voltages.
Student Activity
Questions:
•
What are the different parts of a neuron and what are
their functions?
•
What direction do neurons communicate?
•
What are neurotransmitters?
•
How many neurotransmitters did it take to reach
threshold?
•
What happened to the connection between the
neurons as you added more neurotransmitters?
•
Did the voltages increase or decrease as you added
neurotransmitters?