K+
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.
Sodium ions enter the axon during action potential. This influx of sodium ions depolarizes the axon membrane, leading to the propagation of the action potential along the axon.
The major intracellular ion involved in polarization is potassium (K+). During the resting state of a cell, potassium ions are more concentrated inside the cell compared to the outside, contributing to the negative charge inside the cell relative to the outside. This difference in ion concentration is crucial for maintaining the resting membrane potential and is essential for the proper functioning of nerve and muscle cells during action potentials.
It provides insulation to the axons and dendrites during depolarization or action potential.
In excitable cells such as neurons and muscle cells, the movement of ions across the cell membrane causes polarization and depolarization. Specifically, during polarization, the cell interior becomes more negative due to the influx of potassium ions. In contrast, depolarization involves the influx of sodium ions, leading to a reversal of the membrane potential towards a more positive charge.
During an action potential, the neuron undergoes a rapid change in membrane potential as sodium ions rush into the cell, leading to depolarization. Subsequently, potassium ions move out of the cell, repolarizing the membrane back to its resting state. This rapid change in membrane potential allows for the transmission of electrical signals along the neuron.
During an action potential, the influx of sodium ions (Na+) into the cell causes depolarization, which is the rapid change in membrane potential that makes the inside of the cell more positively charged compared to the outside. This depolarization triggers further opening of voltage-gated sodium channels, allowing even more Na+ to flow in and propagating the action potential along the neuron. As a result, this process is essential for the transmission of electrical signals in the nervous system.
Voltage-gated sodium channels open during the depolarization phase of an action potential, when the membrane potential becomes more positive.
Resting potential
the Nernst potential of Sodium is +60mV. most action potentials do not reach +60mV at peak depoloarization. http://openwetware.org/images/thumb/a/a6/Action-potential.jpg/300px-Action-potential.jpg.png
Sodium ions flow into the neuron via voltage-gated sodium ion channels, driving the membrane potential into the positive. Beyond the threshold, more sodium ion channels are opened, causing the influx of sodium further downstream, and the process repeats, propagating the action potential down the axon.
During the falling phase of the action potential, also known as repolarization, voltage-gated sodium channels close, stopping the influx of sodium ions (Na+). Simultaneously, voltage-gated potassium channels open, allowing potassium ions (K+) to flow out of the neuron. This outflow of K+ causes the membrane potential to become more negative, returning the cell to its resting potential. Ultimately, this phase helps restore the original ionic distribution across the membrane, preparing the neuron for the next action potential.