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The greater influx of sodium ions results in what of the membrane?
Wiki User
∙ 13y ago
depolarization
Wiki User
∙ 13y ago
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A nerve impulse results from?
It results from the opening of voltage-gated sodium ion channels, causing an influx of sodium ions (influx of positively-charged ions), depolarizing the neuronal membrane.
Name the membrane valves that open and close for potassium efflux and sodium influx?
ion channels
What is the reversal of the resting potential owing to an influx of sodium ions called?
Is called depolarization.
The interior of the cell becomes less negative due to an influx of sodium ions?
Depolarization
At the threshold stimulus sodium ions start to move into the cell or out of cell to bring about the membrane depolarization?
For depolarisation to occur as part of an action potential, +40 mV inside the neuron fibre compared to outside the membrane. For summation after a synapse to determine whether the post-synaptic neuron will fire an action potential, the threshold is +20mV inside the neuron compared to the outside.
A nerve impulse results from?
It results from the opening of voltage-gated sodium ion channels, causing an influx of sodium ions (influx of positively-charged ions), depolarizing the neuronal membrane.
Binding of the neurotransmitters with muscle membrane receptors causes the membrane to become permeable to sodium resulting in the influx of sodium ions an what of the membrane?
depolarization
When hinding of the neurotransmitters with muscle membrane receptors causes the membrane to become permeable to sodium resulting in the influx of sodium ions and what membrane?
action potential of the sarcolemma(the membrane)
Name the membrane valves that open and close for potassium efflux and sodium influx?
ion channels
Drugs that decrease membrane permeability to sodium are used as what?
Drugs that decrease membrane permeability to sodium are used as local anesthetics. These drugs block the sodium channels and prevent NA+ from entering the cell. NA+ influx is important to dipolarize the membrane.
Opening of sodium channels in the membrane of a neuron results in?
depolarization.
Does action potential involve the influx of negative ions to depolarize the membrane?
No. The negative ions stay within the cell (neuron).An action potential begins (rising phase) with an influx of sodium, a positive ion or cation. The rising phase ends (falling phase) with an efflux of positive ions (potassium). The membrane potential is stabilized again with the action of the ATP dependent sodium-potassium pump.
What effect of the action potential if sodium channels are kept closed?
The action potential will not generate if the sodium channels are kept closed.This is because the sodium channels are responsible for the dramatic rising phase of membrane depolarization that occurs when the threshold of activation is reached. As a membrane potential gradually depolarizes (which can occur for a variety of reasons such as neurotransmitter stimulation, mechanical deformation of the membrane, etc), that membrane potential gradually comes closer to that threshold of activation. Once that threshold is reached, the voltage gated sodium channels open and allow for a dramatic influx of sodium ions into the cell. This results in a rapid depolarization which is seen as the rising phase of that upward spike noted in an action potential. Without the ability to open these sodium channels we may reach the threshold of activation, but the actual action potential will not occur.
A neuron starts to fire an impulse by the influx of what ions?
sodium
Describe the events occurring in the cell membrane that permit the conduction of an impulse?
When a nerve impulse is conducted, the neuronal cell membrane undergoes changes in electrical potential. This starts with a rapid influx of sodium ions into the cell through voltage-gated sodium channels, depolarizing the membrane. This depolarization triggers the opening of adjacent sodium channels, resulting in an action potential that travels along the membrane. After the impulse passes, the sodium channels close, and potassium channels open, allowing potassium ions to exit the cell and restore the resting potential.
What is the presynaptic neuron release neurotransmitters in response to an influx of?
Sodium ions
An action potential is caused by an influx of these ions into the cell?
sodium ions
