How is a nerve impulse transmitted?

Answer 1

Transmitted between neurons via NEUROTRANSMITTER chemicals; along the neurons dendrites and soma by ELECTROTONIC conduction; and along the axon by the ACTION POTENTIAL (or along myelinated axons by a combination of electrotonic and action potential called SALTATORY CONDUCTION).

The action of a neurotransmitter on a neuron is to open ion pores which allow Sodium ions to enter the neuron. The action along an axon of a neuron is an interchange of Sodium and Potassium ions, which propagates the impulse via the action potential.

note:I don't think Potassium is involved between the nerve cells as indicated below in the original answer. Sodium and Potassium along an axon, Calcium at the end of one neuron, NEUROTRANSMITTERS between them, and Sodium in the beginning of the next one. the original answer:Nerve impulses are transferred as ion exchanges. The ions of Sodium and Postssium are involved in and between the nerve cells.
Across a SYNAPSE, along a DENDRITE and the SOMA, and finally along the AXON. The Synapse:At a SYNAPSE, an impulse from the first (initiating) neuron which has reached that presynaptic neurons axon terminal causes voltage-gated Calcium ion pores to open in that axon terminal, allowing Calcium ions into that axon terminal, which causes small bags (vesicles) of chemicals (neurotransmitters) to merge with the cell membrane at the end of that axon terminal (the beginning of the synapse), releasing the neurotransmitters into the space between two neurons (the synaptic cleft), where they DIFFUSE quickly over to the SECOND neuron, usually at dendrite or dendritic spine, where the neurotransmitters bounce or slide or otherwise fit into the RECEPTOR sites of ligand-gated Sodium PORES on the SECOND or receiving neuron, causing those pores to open, allowing Sodium ions to enter the dendrites of the receiving neuron. Dendrite, and Soma (the body of the Neuron):In and along a DENDRITE & then across the SOMA, the Sodium ions electrostatically "bump" one another, resulting quickly and finally (but with decreasing force) in somewhat of a "pileup" of Sodium ions at the AXON HILLOCK (the place on the neuron where the AXON begins). This is called ELECTROTONIC impulse conduction or transmission. The Axon:If enough dendrites have been stimulated, or one or more have been repeatedly stimulated sufficiently, to cause a big enough pile up of Sodium ions at the axon hillock (ie, resulting in a big enough voltage), then that TRIGGER will open voltage-gated ion pores, allowing more sodium ions in, which opens more voltage-gated ion pores further along the axon, which brings in more sodium ions, which open more voltage-gated pores, etc. This process continues along the axon until it reaches the end of the axon terminals. This mode of impulse conduction is called the ACTION POTENTIAL.

Answer 2

axon