It can be identified using light microscopy from its appearance and location in a neuron and from its sparse distribution of Nissl substance.

[6] This clustering of voltage-gated ion channels is a consequence of plasma-membrane and cytoskeletal associating proteins such as ankyrin.

The triggering is due to positive feedback between highly crowded voltage-gated sodium channels, which are present at the critical density at the axon hillock (and nodes of ranvier) but not in the soma.

If several such events occur in a short time, the axon hillock may become sufficiently depolarized for the voltage-gated sodium channels to open.

Under normal conditions, the action potential would attenuate very quickly due to the porous nature of the cell membrane.

Myelin, a derivative of cholesterol, acts as an insulating sheath and ensures that the signal cannot escape through the ion or leak channels.