Axon Dendrite Cell Body Neuron (Nerve cell) Anatomy Synapse

<strong>Neuron</strong> (<strong>Nerve</strong> <strong>cell</strong>) <strong>Anatomy</strong> <br />

<strong>Cell</strong> <strong>Body</strong><br />

<strong>Dendrite</strong><br />

<strong>Dendrite</strong>s<br />

<strong>Axon</strong><br />

<strong>Axon</strong><br />

<strong>Axon</strong><br />

<strong>Synapse</strong>

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<strong>Dendrite</strong><br />

<strong>Cell</strong> body<br />

unsheathed node<br />

axon<br />

Two Functions: <br />

Insulation <br />

Make nerve impulse faster <br />

Myelin Sheath: <br />

lipid-rich insulation<br />

around <strong>Axon</strong>

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<strong>Nerve</strong> <strong>cell</strong> at rest. Inside of <strong>cell</strong> is negative, outside of <strong>cell</strong> is positive.

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1. Na + channel opens. Na + ions flow into <strong>cell</strong>. <br />

Reverses charge. Now positive inside, negative outside.

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2. Step 1 causes next Na + channel to open, Action Potential moves<br />

along <strong>Axon</strong> away from <strong>cell</strong> body.

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3. K + channels open right after Na + channel.<br />

K + flows out and restores negative charge inside,<br />

positive charge outside.

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4. Sodium-Potassium pump uses ATP energy to pump Na +<br />

back out and K + back in. Membrane potential restored.

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How the myelin sheath speeds nerve impulses <br />

<strong>Cell</strong> body <br />

Next <strong>Nerve</strong> <br />

Na+<br />

action potential Membrane potential Membrane potential<br />

<strong>Axon</strong>

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How the myelin sheath speeds nerve impulses <br />

<strong>Cell</strong> body <br />

Next <strong>Nerve</strong> <br />

K+<br />

Na+<br />

Membrane potential restored<br />

action potential<br />

Membrane potential<br />

<strong>Axon</strong>

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Action<br />

Potential <br />

<strong>Axon</strong><br />

Ca 2+ <br />

Ca 2+ <br />

Ca 2+ <br />

synaptic<br />

vesicle<br />

Ca 2+ <br />

Ca 2+ <br />

membrane receptor<br />

for neurotransmitter<br />

<strong>Synapse</strong><br />

plasma<br />

membrane of<br />

postsynaptic <strong>cell</strong>