How Neurons Signal Electrically: An Insight
Neurological Disorders
Lesson 2.2
How do our neurons signal
electrically?
Electrical
Signal
Do Now:
•
Ethan needs to have a
cavity filled. Before his
doctor begins drilling, she
gives him Novocain to
prevent pain.
•
How do you think Novocain
works???
–
Novocain stops our neurons
from signaling electrically.
–
But how do our neurons
signal electrically???
Neurons Send Signals
•
Chemically via synapses
•
Electrically via axons
Chemical
Signal
Electrical
Signal
Electrical
Signal
Electrical
Signal
Chemical
Signal
•
Axons signal electrically in a process called the
Action Potential.
Electrical
Signal
The Axon’s Electrical Signal:
The Action Potential
Before we model the Action Potential, let’s
review:
Diffusion
?
Diffusion of Sodium Ions (Na
+
)
Na
+
Na
+
Na
+
Na
+
Na
+
Na
+
Na
+
Na
+
Na
+
?
Before we model the Action Potential,
let’s review:
The Cell Membrane
The Cell Membrane
•
What causes the Na
+
channels to open?
–
Na
+
channels open at
Threshold
.
Closed
Na
+
channel
Open
Na
+
channel
Why would
Na+ want to
move?
Before we model the Action Potential, let’s
review:
Threshold
•
How do you flush a toilet?
•
What if you just gently
jiggle the handle? Will the
toilet flush?
•
Can you stop a toilet from
flushing after it’s started to
flush?
Getting to Threshold
•
When a neuron receives signals from another
neuron it may reach threshold.
•
If threshold is reached, Na
+
channels open.
Electrical
Signal
Getting to Threshold
Signal from
another neuron
Modeling the Action Potential
Outside
Inside
Toothpick = Na
+
ion channel
Bean = Na
+
ion
Open channel
Closed channel
Model of the Action Potential
Signal from
another neuron
Action Potential
•
Based on the principle of diffusion, where will the Na+ go once the Na+
channels open?
•
It will enter the axon, because it is a lower concentration inside the axon
•
Action Potential
How does Novocain work?
•
It plugs the toilets!
Pain Signal
Out of
Order
Out of
Order
Out of
Order
How does Novocain work?
–
The axon can’t send Action Potentials.
–
Meaning you can’t feel pain!
Novocain
Novocain
Novocain
•
What happens if the Na
+
channels can’t open?
Pain Signal
No Signal
Explore the process of neuronal signaling via electrical and chemical signals, focusing on the action potential and threshold concept. Learn about Novocain's role in blocking neuronal electrical signaling and the dynamics of sodium ion diffusion. Dive into the intricacies of cell membrane function and the significance of reaching threshold in electrical signaling between neurons.
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Presentation Transcript
Neurological Disorders Lesson 2.2 How do our neurons signal electrically? Electrical Signal
Do Now: Ethan needs to have a cavity filled. Before his doctor begins drilling, she gives him Novocain to prevent pain. How do you think Novocain works??? Novocain stops our neurons from signaling electrically. But how do our neurons signal electrically???
Neurons Send Signals Electrical Signal Electrical Signal Electrical Signal Chemical Signal Chemical Signal Chemically via synapses Electrically via axons
The Axons Electrical Signal: The Action Potential Electrical Signal Axons signal electrically in a process called the Action Potential.
Before we model the Action Potential, lets review: Diffusion ?
Diffusion of Sodium Ions (Na+) Na+ Na+ Na+ Na+ Na+Na+ Na+Na+ Na+ Na+ Na+ ? Na+ Na+ Na+ Na+ Na+ Na+ Na+
Before we model the Action Potential, let s review: The Cell Membrane
The Cell Membrane Why would Na+ want to move? Na+ Na+ Na+ Na+ Closed Na+ channel Open Na+ channel What causes the Na+ channels to open? Na+ channels open at Threshold.
Before we model the Action Potential, lets review: Threshold How do you flush a toilet? What if you just gently jiggle the handle? Will the toilet flush? Can you stop a toilet from flushing after it s started to flush?
Getting to Threshold Electrical Signal When a neuron receives signals from another neuron it may reach threshold. If threshold is reached, Na+ channels open.
Getting to Threshold Signal from another neuron
Modeling the Action Potential Bean = Na+ ion Closed channel Outside Open channel Inside Toothpick = Na+ ion channel
Model of the Action Potential Na+ Na+ Na+ Na+ Na+ Na+ Na+ Signal from another neuron Na+ Na+ Na+ Na+ Na+ Action Potential Based on the principle of diffusion, where will the Na+ go once the Na+ channels open? It will enter the axon, because it is a lower concentration inside the axon Action Potential
How does Novocain work? It plugs the toilets! Out of Order Out of Order Out of Order Pain Signal
How does Novocain work? What happens if the Na+channels can t open? Novocain Novocain Novocain Pain Signal No Signal The axon can t send Action Potentials. Meaning you can t feel pain!
