Biology 12 (16-17) L 48 Date: May 8
| Last lessons Objective |
1. Intro to Nervous System |
Evaluations
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| Today’s Objective | 1. Review Neuron structures
2. Action Potential 3. Action Potential Sheets
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| Topic One | It is a neuron and not a nerve!
Intro video https://www.youtube.com/watch?v=DLN1UsvmVvM
Tricks: There are five distinct cell structures that allow you to classify three neuron types. Key questions: Were is the cell body? Which is longer, axon or dendrites? Which cell types have myelin
2 minute lesson https://www.youtube.com/watch?v=6qS83wD29PY
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| Topic
Two |
How do you make a wave?
Lets start with basic wave structures. You have a high point and a low point. On a y axis, this high and low in action potentials is in millivolts. Simplified, voltage is the amount of “push”.
Bozeman https://www.youtube.com/watch?v=HYLyhXRp298
So breaking it down into three steps there is Depolarization Inside the actual neuron, the voltage is shifting from negative to positive. This is done by the inflow of sodium into the axon. Outside of the axon, the charge shifts from positive to negative. Note which way “the wave” moves. Repolarization Once the action potential reaches it’s peak, then the charge needs to shift from positive to negative. Now, potassium moves out of the cell, shifting the voltage back to negative. Recovery Period Now the cell become too negative and so some fine tuning is needed via active transport, to move some sodium in and at the same time move potassium out. So let’s find some “links” to visualize this process. A simple step by step video https://www.youtube.com/watch?v=ZAmUjvgoO0A
Khan academy feedback
Entering “sodium gates” https://www.youtube.com/watch?v=qDUjVzVq7xE
Like this one https://www.youtube.com/watch?v=ooI7xT59hE8
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| Topic
Three |
So here are some key focal points
1) It is the movement of Sodium going into the cell and the movement of potassium going out of the cell that generates “the wave”. 2) This wave can be faster by moving from “node to node” verses opening several gates in a sequence. 3) Action potential starts with a specific electrical voltage within the axon. This is an all or nothing phenomena. You either have the initial voltage to start the wave or you have no message sent. 4) This process involves four protein carriers. One is active transport during the recovery period. 5) If you think you have seen this graph before, you are right. Remember the circulatory system?
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| Text Ref |
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| You tube |
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| Class Notes | Types of neurons.
Action potential
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