Axon Dendrite Cell Body Neuron (Nerve cell) Anatomy Synapse

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Axon Dendrite Cell Body Neuron (Nerve cell) Anatomy Synapse

Neuron (Nerve cell) Anatomy

Cell Body

Dendrite

Dendrites

Axon

Axon

Axon

Synapse


Dendrite

Cell body

unsheathed node

axon

Two Functions:

Insulation

Make nerve impulse faster

Myelin Sheath:

lipid-rich insulation

around Axon


Nerve cell at rest. Inside of cell is negative, outside of cell is positive.


1. Na + channel opens. Na + ions flow into cell.

Reverses charge. Now positive inside, negative outside.


2. Step 1 causes next Na + channel to open, Action Potential moves

along Axon away from cell body.


3. K + channels open right after Na + channel.

K + flows out and restores negative charge inside,

positive charge outside.


4. Sodium-Potassium pump uses ATP energy to pump Na +

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


How the myelin sheath speeds nerve impulses

Cell body

Next Nerve

Na+

action potential Membrane potential Membrane potential

Axon


How the myelin sheath speeds nerve impulses

Cell body

Next Nerve

K+

Na+

Membrane potential restored

action potential

Membrane potential

Axon


Action

Potential

Axon

Ca 2+

Ca 2+

Ca 2+

synaptic

vesicle

Ca 2+

Ca 2+

membrane receptor

for neurotransmitter

Synapse

plasma

membrane of

postsynaptic cell

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