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What is The region of a neuron with voltage-gated sodium channels?
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∙ 12y ago
soma
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∙ 12y ago
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Opening sodium channels in the in the axon membrane causes?
Depolarization of the cell membrane. When the sodium channels open there is a rush of sodium ions down their concentration gradient into the cell. As they carry positive charge they reduce the potential difference (inside negative) across the membrane of the neuron.
How does a neuron create a positive feedback loop?
through what can be seen as the domino effect. when depolarization opens sodium ion channel and that results to the opening of more sodium ion channels. this creates a positive feedback loop.
What would happen if a chemically gated sodium channel in the postsynaptic membrane were completely blocked?
The nervous system would not work if ion channels were blocked. It would be like parking your car on a hose and trying to get water out of the hose.
When cholinergic receptors are stimulated they?
sodium ions enter the postsynaptic neuron.
What initiates the depolarization of the neuron?
Most neurons are at a negative membrane potential so when a ligand operated channel opens there is an inflow of positively charged ions, mostly but not exclusively sodium. If the neuron cell membrane has voltage-operated channels (the textbook example) then the inflow of positive ions can open the voltage-operated channels causing an even greater flow of positive ions into the neuron. This positive feed arrangement can lead to the neuron transitioning from negative to respect to outside of the cell to positive (overshoot). Since the voltage-operated channels inactive and also due to the potassium specific channels the cell is returned it's pre-action potential negative level (close to potassium's equilibrium potential).
What happens to the neuron if sodium channels do not open?
causes chemically gated sodium channels to open
Opening of sodium channels in the membrane of a neuron results in?
depolarization.
The start of an action potential?
An action potential starts when sodium channels in a neuron end open and sodium ions rush is, depolarizing the neuron's membrane.
How do non functional sodium channels affect the signaling capabilities of neurons?
When sodium enters the neuron, it depolarizes it. This means that the neuron becomes more positive. This can lead to the neuron reaching threshold and then initiate an action potential. When the sodium channels are NOT functional, the sodium can not enter and depolarize it. Therefore the threshold can not be met and action potential will not occur. If the sodium channels are inactive in an nociceptive neruon (carries information about pain), then the it will prevent you from feeling pain.
How is an action potential propagated down an axon after voltage-gated sodium channels open in a region of the neuron's membrane?
The entry of sodium ions into the neuron and their diffusion to adjacent areas of the membrane causes those portions of the membrane to become depolarized and results in the opening of voltage-gated sodium channels farther down the axon, which release potassium ions to the outside, returning the charge to its previous state
What changes occur in the neuron?
Neurons undergo depolarization and repolarization when stimulated. The sodium and potassium channels open.
Effects of lidocaine on nerves?
it prevents sodium channels from opening which removes a neuron's resting membrane potential
What molecularly happens a neuron affected by lidocaine?
Lidocaine is what is called an open sodium channel blocker. This means that it binds preferentially to sodium channels when they are in the open (letting sodium into the cell) state.
What helps maintain the resting potential of a neuron?
During resting potential, the Sodium-Potassium pump is inactive. Therefore, it is indirectly responsible for the resting potential. However, Potassium diffuses outside the membrane via "leakage" channels, and causes the resting potential.
In action potential the sodium enter to depolarize the stimulated area not whole the nerve why?
Sodium ions can enter the neuron in the stimulated areabecause in this area sodium channels open up, allowing the sodium ions to flow down their concentration gradient. In other parts of the membrane these channels remain closed.
Opening sodium channels in the in the axon membrane causes?
Depolarization of the cell membrane. When the sodium channels open there is a rush of sodium ions down their concentration gradient into the cell. As they carry positive charge they reduce the potential difference (inside negative) across the membrane of the neuron.
How will preventing the inactivation of sodium channels affect the signaling capability of a neuron?
When sodium channels are not active, it means that the capability of neurons to send the electronic signals in the body weakens. Neurons are nerve cells that communicate by passing Na+ and K+ ions.
