by "sodium pump", a process involving active transport
No. Three sodium ions are pumped out of the neuron by the sodium-potassium pump and two potassium ions enter the cell. This way you maintain a slightly negative charge just inside the cell membrane.
A neuron fires an impulse by the influx of sodium ions into the cell. This creates a temporary change in the neuron's membrane potential, leading to depolarization and the generation of an action potential.
False( When a stimulus acts on a neuron, it increases the permeability of the stimulated point of its membrane to sodium ions. )
A neuron that is polarized is also at rest potential. At this stage it is not conducting an impulse and has sodium ions on the outside and potassium ions on the inside.
The sodium-potassium pump is responsible for maintaining the resting membrane potential of a neuron by actively pumping sodium ions out of the cell and potassium ions into the cell, against their concentration gradients. This creates an imbalance of ions across the membrane, contributing to the resting potential of the neuron.
Sodium ions
This state is known as depolarization. It occurs when there is a rapid influx of sodium ions into the neuron, causing the inside of the neuron to become more positively charged compared to the outside.
Sodium ions are concentrated on the outside of the neuron due to the action of the sodium-potassium pump, which actively transports sodium out of the cell in exchange for potassium. This helps maintain the neuron's resting membrane potential and creates a concentration gradient favoring the movement of sodium into the cell during an action potential.
When a neuron depolarizes, sodium ions rush into the axon through voltage-gated sodium channels. This influx of sodium ions causes the inside of the neuron to become more positively charged, propagating the electrical signal along the axon in the form of an action potential.
Depends on what stage you are talking about. Stimulus of sodium ions from dendrites of other neurons must reach a threshold. Once that threshold is reached, sodium ions quickly diffuse into the neuron via facilitative diffusion, depolarizing the neuron. Upon this occurring, sodium channels close and potassium ions are pumped out of the neuron via active transport, leading to repolarization of the neuron.
The main ions found inside a neuron are potassium and organic anions. The organic anions cannot cross the cell membrane but potassium ions can. It is the diffusion of potassium ions out of the cell which is the main cause of the resting membrane potential.
The resting potential is the normal equilibrium charge difference (potential gradient) across the neuronal membrane, created by the imbalance in sodium, potassium, and chloride ions inside and outside the neuron.