1.4di - Nerve Impulse Transmission Flashcards
Resting membrane potential is…
a state where there is no net flow of ions across the membrane
The transmission of a nerve impulse requires…
changes in the membrane potential in the neuron’s plasma membrane
An action potential is…
a wave of electrical excitation along a neuron’s plasma membrane
Neurotransmitters initiate a response by…
binding to their receptors at synapse
Neurotransmitter receptors are…
ligand-gated channels
Entry of the positive ions causes…
the depolarisation of the plasma membrane
Depolarisation of the plasma membrane triggers…
the opening of voltage-gated sodium channels, and further depolarisation occurs
Depolarisation is…
a change in the membrane potential to a less negative value inside
What restores the resting membrane potential?
inactivation of the sodium channel and the opening of potassium channels
Binding of a neurotransmitter triggers…
the opening of ligand-gated ion channels at a synapse
Ion movement occurs and…
there is depolarisation of the plasma membrane
What triggers the opening of voltage-gated sodium channels?
if sufficient ion movement occurs, and the membrane is depolarised beyond a threshold value
The opening of voltage-gated sodium channels causes…
sodium ions to enter the cell down their electrochemical gradient, leading to a large and rapid change in the membrane potential
A short time after opening, the sodium channels…
become inactivated
After the sodium channel are deactivated…
voltage-gated potassium channels open to allow potassium ions to move out of the cell to restore the resting membrane potential
Depolarisation of a patch of membrane causes…
neighbouring regions of membrane to depolarise and go through the same cycle, as adjacent voltage-gated sodium channels are opened
When the action potential reaches the end of the neuron it causes…
vesicles containing neurotransmitters to fuse with the membrane, which releases a neurotransmitter, stimulating a response in a connecting cell
Restoration of the resting membrane potential allows…
the inactive voltage-gated sodium channels to return to a conformation that allows them to open again in response to depolarisation of the membrane
Ion concentration gradients are re-established by…
the sodium-potassium pump, which actively transports excess ions in and out of the cell
Following repolarisation…
the sodium and potassium ion concentration gradients are reduced
The sodium-potassium pump restores…
the sodium and potassium ions back to resting potential levels
