despolarization
depolarization
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.
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.
During an action potential, voltage-gated ion channels open in response to depolarization, causing an influx of sodium ions into the cell. This influx of positive ions triggers the reversal of charge inside the membrane, producing an action potential.
Self-propagated depolarization refers to the process by which an action potential triggers the opening of voltage-gated ion channels along the membrane, causing further depolarization in adjacent regions of the neuron. This process allows the action potential to travel down the length of the neuron, enabling rapid communication within the nervous system.
Yes, this threshold is known as the neuron's resting membrane potential. When the depolarization reaches -55 mV, it triggers the opening of voltage-gated sodium channels, leading to the rapid influx of sodium ions and generating an action potential. This initiates the propagation of the electrical signal along the neuron.
The action potential begins when the neuron is stimulated and reaches a certain threshold of excitation. This causes voltage-gated ion channels to open, allowing a rapid influx of sodium ions into the neuron, leading to depolarization. This depolarization triggers a cascading effect along the neuron's membrane, resulting in the propagation of the action potential.
The action potential has 5 main phases:1) stimulation/rising phase - depolarization caused by influx of sodium ions at the axon hillock; potential increases from a resting potential of -70 mV2) peak phase - depolarization and membrane potential reaches a peak, with sodium channels open maximally, at about +40 mV3) falling phase - potassium channels open in response, causing a subsequent reduction in membrane potential, and the neuron begins to repolarize4) hyperpolarization/undershoot phase - more potassium channels stay open after sodium channels close, causing a hyperpolarization of the neuronal membrane, bringing the potential down below its initial resting potential (below -70 mV)5) refractory phase - potassium channels begin to close, allowing the membrane potential to revert back to the resting potential of -70 mV; during this phase, the probability of the nerve being able to refire is extremely low, thus allowing for a delay between action potentials
Depolarization of a neurotransmitter refers to the shift in the electrical charge of the neuron, making it more likely to generate an action potential. This can occur when a neurotransmitter binds to its receptor on the postsynaptic membrane, causing ion channels to open and allowing the influx of positively charged ions. This depolarization triggers a series of events that lead to the transmission of the nerve signal.
An action potential is self-regenerating due to the depolarization phase, where sodium channels open in response to membrane depolarization, leading to an influx of sodium ions that further depolarizes the membrane and triggers adjacent sodium channels to open. This positive feedback loop allows the action potential to propagate along the axon without losing strength.
The threshold potential must be reached for the neuron to fire. This is the level of depolarization that triggers an action potential to be generated and propagated along the neuron.
Disturbances to sensory neurons can cause depolarization of the neuron's membrane, reaching a threshold that triggers an action potential. This action potential then travels along the neuron's axon to the central nervous system, where it is processed and interpreted as a sensory experience.