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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.
What else can I help you with?
The greater influx of sodium ions results in what of the membrane?
The greater influx of sodium ions results in membrane depolarization. This is because sodium ions carry a positive charge, which leads to a decrease in the membrane potential towards zero or a positive value.
The combining of the neurotransmitter with the muscle membrane receptors causes the membrane to become permeable to sodium ions and blank of the membrane?
The combining of the neurotransmitter with the muscle membrane receptors causes the membrane to become permeable to sodium ions and depolarization of the membrane. This depolarization triggers an action potential that leads to muscle contraction.
When do voltage gated sodium channels open in the process of neuronal signaling?
Voltage-gated sodium channels open when the membrane potential reaches a certain threshold during the depolarization phase of neuronal signaling.
What is the reversal of the resting potential owing to an influx of sodium ions called?
The reversal of the resting potential owing to an influx of sodium ions is called depolarization. This occurs when the membrane potential becomes less negative, bringing it closer to the threshold for action potential initiation.
Triggering of the muscle action potential occurs after?
depolarization of the cell membrane reaches a threshold level. This threshold is usually around -55mV. Once threshold is reached, voltage-gated sodium channels open, allowing sodium ions to rapidly enter the cell and generate an action potential.
What characterizes depolarization the first phase of the action potential?
Depolarization is the initial phase of the action potential characterized by a rapid influx of sodium ions into the cell, causing a change in membrane potential from negative to positive. This occurs when voltage-gated sodium channels open in response to a threshold stimulus, leading to the depolarization of the cell membrane.
Why are most action potentials generated in response to a long stimulus that is above threshold?
Action potentials are generated in response to a long stimulus above threshold because it allows for the full development of the depolarization phase. This prolonged depolarization leads to the activation of voltage-gated sodium channels, triggering the rapid influx of sodium ions and initiating the action potential. A sustained stimulus ensures that the membrane potential remains above threshold for a sufficient time to generate an action potential.
When a nerve is activated by a threshold stimulus the membrane becomes more permeable to?
Potassium and Sodium
Why don't the terms depolarization and action potential mean the same thing?
Depolarization occurs when a stimulus opens sodium channels which allow more sodium to go into the membrane making it less negative and more positive (toward reaching threshold). An action potential can only occur once the membrane reaches threshold which means it has reached the level needed through depolarization. An action potential is a brief reversal in polarity of the membrane making the inside more positive and the outside more negative, the reverse occurs again once the membrane reaches resting potential.
Depolarization of the nerve membrane begins with?
The opening of voltage-gated sodium channels in response to a stimulus. Sodium ions flow into the cell, causing depolarization as the inside becomes more positively charged.
The action potential is generated when a stimulus?
The action potential is generated when a stimulus causes a change in the electrical potential across the cell membrane, resulting in the opening of voltage-gated ion channels. This allows an influx of sodium ions, causing depolarization of the membrane and initiation of the action potential.
What opens first in response to a threshold stimulus?
The activation gates of voltage-gated Na+ channels open, and Na+ diffuses into the cytoplasm.
The greater influx of sodium ions results in what of the membrane?
The greater influx of sodium ions results in membrane depolarization. This is because sodium ions carry a positive charge, which leads to a decrease in the membrane potential towards zero or a positive value.
When ACh receptors open what ion causes depolarization of the postsynaptic membrane?
When acetylcholine (ACh) receptors open, sodium ions (Na+) primarily flow into the postsynaptic membrane. This influx of positively charged sodium ions leads to depolarization, making the inside of the cell more positive. If the depolarization reaches a certain threshold, it can trigger an action potential in the postsynaptic neuron.
What ion is rapidly moving into the cell during the depolarization period of an action potential?
Sodium.A positive ion (cation) that enters the cell (influx) rapidly when the membrane threshold is reached and the voltage gated sodium channels open.This occurs during the rising phase of an action potential, i.e. membrane depolarization beyond the threshold for activation.
The combining of the neurotransmitter with the muscle membrane receptors causes the membrane to become permeable to sodium ions and blank of the membrane?
The combining of the neurotransmitter with the muscle membrane receptors causes the membrane to become permeable to sodium ions and depolarization of the membrane. This depolarization triggers an action potential that leads to muscle contraction.
What happen during the rising phase of an action potential?
During the rising phase of an action potential, voltage-gated sodium channels open in response to a depolarizing stimulus. This allows sodium ions to rush into the cell, causing a rapid depolarization of the cell membrane. This results in the cell reaching its threshold and firing an action potential.
