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What is a resting motor neuron expected to do?
exhibit a resting potential that is more negative than the "threshold" potential
A neuron fires only when its membrane reaches what?
A neuron fires when its membrane reaches a certain threshold potential. This threshold potential is typically around -55 to -65 millivolts. When the membrane potential reaches this level, an action potential is triggered and the neuron fires.
Membrane potential required to achieve threshold?
-55mV
What change in membrane potential triggers an action potential?
A sudden increase in membrane potential, typically from a resting membrane potential of around -70mV to a threshold potential of around -55mV, triggers the opening of voltage-gated sodium channels leading to depolarization and initiation of an action potential.
Which is greater - The extent of membrane polarization at threshold potential or that of the resting membrane potential?
A cell is more depolarized at it's threshold potential than it is at it's resting potential. This is important because a nervous system where a random excitatory post synaptic potential (epsp) would trigger the next neuron would lead to an overly excitable nervous system (btw, this is why caffeine makes you jittery).
What is a resting motor neuron expected to do?
exhibit a resting potential that is more negative than the "threshold" potential
A neuron fires only when its membrane reaches what?
A neuron fires when its membrane reaches a certain threshold potential. This threshold potential is typically around -55 to -65 millivolts. When the membrane potential reaches this level, an action potential is triggered and the neuron fires.
Membrane potential required to achieve threshold?
-55mV
What change in membrane potential triggers an action potential?
A sudden increase in membrane potential, typically from a resting membrane potential of around -70mV to a threshold potential of around -55mV, triggers the opening of voltage-gated sodium channels leading to depolarization and initiation of an action potential.
Which is greater - The extent of membrane polarization at threshold potential or that of the resting membrane potential?
A cell is more depolarized at it's threshold potential than it is at it's resting potential. This is important because a nervous system where a random excitatory post synaptic potential (epsp) would trigger the next neuron would lead to an overly excitable nervous system (btw, this is why caffeine makes you jittery).
A resting motor neuron is expected to?
exhibit a resting potential that is more negative than the "threshold" potential.
When a stimulus is sufficiently great enough to change the membrane potential and propagate an action potential it is called?
recruitement
What does it take to trigger an action potential?
neurotransmitters from the presynaptic neuron must be released and binded to the ligand gated sodium channels to increase the membrane potential (increase the charge) until it reaches the threshold of the trigger zone which is -55 millivolts.
What is sub threshold Depolarization of nerves?
Sub threshold depolarisation of nerves, would be the influx of sodium (and maybe efflux of potassium depending) that doesn't cause enough depolarisation for an action potential to be fired. The summation of sub threshold depolarisations may cause an AP to be released. if they 'tip the balance' far enough. Hope this helps Edit: Above answer is vague. Sub threshold depolarizations do not occur as a result of efflux of potassium, which hyperpolarizes a neuron. They can be generated as EPSPs at the post synaptic membrane or result from persistant sodium channels, which do not completely inactivate (contributing to pacemaking activity). In both cases, gradual depolarization can lead to action potential generation.
What is a sub-threshold change in membrane potential within the cell body that decays as it travels away from its point of origin?
A sub-threshold change in membrane potential in the cell body, such as an excitatory post-synaptic potential (EPSP), does not reach the threshold for action potential initiation. As it travels along the dendrites and cell body, it decays and dissipates, failing to trigger an action potential. This phenomenon is crucial in the integration of signals by neurons.
Is an action spike an impulse created by an excitable membrane when it reaches the threshold?
Yes, an action potential spike is generated when the membrane potential of a neuron reaches a certain threshold, causing a rapid depolarization and repolarization of the membrane. This creates a brief electrical impulse that propagates along the neuron's axon.
How are potential and action potential related?
Resting potential and action potential are both names for the measure of electrical voltage within the membrane of a cell. Specifically, these terms are used in describing the transfer of information along neural pathways. Resting potential is a state where cells are at rest. However, if an electrical response or depolarization reaches threshold, then ion channels open, allowing sodium ions to rush into the membrane and increase the voltage measure, firing an action potential along the length of this membrane.
