Action Potential Flashcards
What two reactions cause a signal to be transmitted?
electronically via action potential
Chemically via neuro transmitters
What is the mv of respting potential?
-70mv
Why is it a negative charge inside the cell?
The large negatively charged protein molecules inside the neuron cannot cross the membrane. In addition to these selective ion channels, there is a pump that uses energy to move three sodium ions out of the neuron for every two potassium ions it puts in.
What are the 4 main pumps/channels involved in a neuron?
Sodium/potassium pump
Sodium channel
Potassium channel
Calcium channel
What sort of transport is used with the sodium potassium pump and the potassium/sodium channels?
Active transport. ATP is used for the pump and facilitative diffusion transport for the channels.
What is depolarisation, and when does it happen?
Depolarization refers to the sudden change of charge in a positive direction within a cell.
What is the threshold when talking about AP?
This is the point of no return. It is at -35 mV
What is the next stage after Depolarisation?
Repolarisation. This is where the neuron returns to -70mv
What can happen after Repolarisation?
Hyperpolarisation. This is when the expelling of potassium via the channels goes too far in negativity. Na/K pump regulates this.
What is the area at the end of axon terminals called?
Synaps cleft.
What are the 6 main areas or items involved in the synaptic transmission and what part do they play?
Neurotransmitters - Chemicals that carry the signal from neuron to neuron
Neuro receptors- receivers collecting the neurotransmitter
Pre synaptic neuron - The left/leaving neuron
Post synaptic neuron - The receiving/right neuron
Synaptic Vesicles - Sacks that contain the neurotransmitters
Calcium ion channels - Channels that open to encourage vesicle and membrane bonding.
What happens the the ‘left over’ neuro transmitters?
The are absorbed by enzymes, removed by the blood or taken back up by the presynaptic neuron.
What is continuous conduction?
The name given to the traveling signal on a unmyelinated neuron
What is salutatory conduction?
The name given to the traveling signal on a myelinated neuron
What is Absolute Refractory Period?
After an action potential the neuron cell membrane can not be excited again straight away;
This is because the ion channels are recovering and can not be made to open.
