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.
The membrane potential must depolarize from the resting voltage of -70 mV to a threshold value of -55 mV.
The first thing need to start an action potential is a stimulus.
You need enough simulation for the neurons to pass the message to the next neuron. So enough postives in the dendrite to fire the messangers. Which results in a action potential.
depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment
if the graded potential of threshold size reaches a trigger zone
An action potential needs to occur to trigger the neurons but the action potential depends on whether a stimulus is able to bring the membrane potential to a certain level termed the THRESHOLD. This threshold is about -55 mV for most neurons, but the stimulus needs to bring the membrane potential to this certain level or it will not be triggered. Relating to the ALL-OR-NONE PRINCIPLE, which if the threshold is not acquired then an action potential will not occur but once a stimulus is strong enough to depolarize (making the inside of the cell less negative going from -70 mV to -55 mV) it will trigger. The resting potential is -70 mV which the stimulus needs to bring it up to -55mV.
An action potential is triggered when a sufficiently strong neural signal reaches the trigger zone of a neuron, which is the axon hillock or the initial segment of the axon.The trigger zone contains a dense concentration of voltage-gated sodium-ion pores, which open and allow sodium ions into the neuron when the membrane voltage there rises from about -70mV resting potential to a trigger threshold of about -55mV as a result of a summing of inputs to the neuron.The resulting inrush of sodium ions through the ion pores is the beginning of the action potential.
The nerve impulse (action potential) either occurs, or it doesn't, depending on whether or not a sufficient summation of inputs from dendrites at the axon hillock (the trigger point) has occurred, either temporally or spatially.That is, if a large enough number of dendrites have received inputs from other neurons such that their total contribution of electrotonic impulses to the axon hillock results in enough Na ions there to trigger the action potential, or, if one or more dendrites is/are stimulated so often or quickly that, again, there are enough Na ions pushed to the axon hillock to trigger the action potential, then the nerve will "fire". If not enough Na ions are caused to congregate at the axon hillock by either means, then the action potential will not occur, and there will be no transmission of a nerve impulse.
depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment
if the graded potential of threshold size reaches a trigger zone
They are fibres which generate AP(action potential) which trigger heart contractions.
A synapse and an action potential have a flip-flopping cause and effect relationship, in that an action potential in a presynaptic neuron initiates a release of neurotransmitters across a synapse, which can then subsequently potentially trigger an action potential in the axon of the postsynaptic neuron, which would then cause release of neurotransmitters across a following synapse.
Action potential is nerve impulse triggered when a neuron reaches its threshold, or trigger point for firing. Threshold trigger point for a neuron's firing about negative 50 millivolts.
A trigger is an action or device that initiates a subsequent action.
An action potential needs to occur to trigger the neurons but the action potential depends on whether a stimulus is able to bring the membrane potential to a certain level termed the THRESHOLD. This threshold is about -55 mV for most neurons, but the stimulus needs to bring the membrane potential to this certain level or it will not be triggered. Relating to the ALL-OR-NONE PRINCIPLE, which if the threshold is not acquired then an action potential will not occur but once a stimulus is strong enough to depolarize (making the inside of the cell less negative going from -70 mV to -55 mV) it will trigger. The resting potential is -70 mV which the stimulus needs to bring it up to -55mV.
Local polarization is the first step. Next the generation and propagation of an action potential. Lastly repolarization has to take place.
An action potential is triggered when a sufficiently strong neural signal reaches the trigger zone of a neuron, which is the axon hillock or the initial segment of the axon.The trigger zone contains a dense concentration of voltage-gated sodium-ion pores, which open and allow sodium ions into the neuron when the membrane voltage there rises from about -70mV resting potential to a trigger threshold of about -55mV as a result of a summing of inputs to the neuron.The resulting inrush of sodium ions through the ion pores is the beginning of the action potential.
when the voltage of the stimulus is increased above threshold, it can instantly trigger the action potential into a depolarizing state which will rapidly shoot up above the threshold value.
The nerve impulse (action potential) either occurs, or it doesn't, depending on whether or not a sufficient summation of inputs from dendrites at the axon hillock (the trigger point) has occurred, either temporally or spatially.That is, if a large enough number of dendrites have received inputs from other neurons such that their total contribution of electrotonic impulses to the axon hillock results in enough Na ions there to trigger the action potential, or, if one or more dendrites is/are stimulated so often or quickly that, again, there are enough Na ions pushed to the axon hillock to trigger the action potential, then the nerve will "fire". If not enough Na ions are caused to congregate at the axon hillock by either means, then the action potential will not occur, and there will be no transmission of a nerve impulse.
It creates an action potential