Down the dendrites to towards the centre of the cell body.
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The coating covering the axon is called the...?
Myelin Sheath
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The Schwann Cells produce...?
The Schwann cells produce the myelin sheaths around the axons.
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The Nucleus of the Schwann Cell is located...?
In the Myelin Sheath.
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The gaps between the myelin sheaths are called...?
The Nodes of Ranvier
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The end of a nerve cell is called...?
The axon terminal.
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The axon terminal is connected to...?
An effector or another nerve/neurone.
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Pressure on a baroreceptor (Pacinian Corpuscle) causes...?
Stretch-mediated sodium channels to open, allowing sodium ions to diffuse in.
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The sodium ions from the stretch mediated sodium channels...?
Travel up the axon until the myelin sheath is reached.
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In the Node of Ranvier, more...?
Sodium ions diffuse into the axon(until a charge of 40mV is reached and the voltage gated sodium channels close), creating a positive charge (of 40mV) inside the axon, and a negative charge outside the axon.
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At the other end of the myelin sheath, there is a...?
Negative charge.
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The positive charge moves through...?
The myelin sheath to the Node of Ranvier.
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Sodium ions are then then pumped out of the axon through what?
Pumped out of the the axon (using a sodium/potassium pump), and move back (along the concentration gradient) to their original Node of Ranvier.
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Sodium ions on the outside of the axon then...?
Then diffuse into the Node of Ranvier to allow for the process to start again.
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The movement of the action potential (sodium ions) through/around the myelin sheath is called...?
Saltatory Conduction
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What is the resting potential inside an axon?
-65mV to -70mV
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How is the resting potential created?
Through the active transport of sodium ions out of the axon (until a potential of 40mV is reached outside the cell) and the active transport of potassium ions into the axon through a Na+/K+ pump, until a charge of -65 to -70mV is reached.
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A Na+/K+ pump (Sodium Potassium pump) moves...?
Three sodium ions out of the axon and two potassium ions into the axon.
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Some potassium...
Moves out of the axon through the 'leaky' potassium channels.
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What does the Threshold Potential do?
The threshold potential acts as a filter on the stimulus.
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What is the voltage of the threshold potential?
-55mV
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If a stimuli isn't strong enough to change the potential to -55mV...?
An action potential will not be triggered.
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The movement of sodium ions into the axon is called...?
Depolarisation
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The active transport of sodium ions out of and potassium ions into the axon is called...?
Repolarisation
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What happens in repolarisation?
3Na+ are pumped out and 2K+ are pumped into the axon.
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The ...? also open in repolarisation.
Potassium channels
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The time after a stimulus where a nerve is unresponsive to any more stimuli is called...?
The refractory period
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The refractory period limits the number of action potentials to...?
an average of 100/s
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There can only be one action potential in the...?
Absolute refractory period.
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Above 0mV there has to be...?
A period of repolarisation to allow for another action potential.
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