Answer:
Cell surface membrane.(Axolemma)
Explanation:
These membranes encasing the neuron is perforated by ion channels, which allow diffusion of ions with their charges across it down their electrochemical gradients. <u>These ion channels are specific to a particular ion, while restricting others.</u> E,g sodium-potassium pump , are special ion channels in axon cell membrane with specif channels for sodium ions, and will not allow the passage of potassium through the same channels and vice-versa.
<em>There are two types on these ion channels based on what controls their openings.</em>
<u>The voltage gated ion channels which are controlled by the electrical potential or voltage generated across the axon.And the ion channels control by the electrochemical gradients of the ions moving across the membrane.</u>
The reversal of the charges of these ions across it (axonlemma) create membrane potential down the length of the membrane. This set up a voltage change inside the Axoplasm(cytoplasm of the axon). If this voltage is up to the threshold it creates depolarization of the ( ion channels)with influx of sodium ions, while the potassium ions channels are shut up.
Furthermore, if the stimulation of the neuron is intense, and the membrane potential increases up to the threshold level the electrical potential energy generated cause the (<u>voltage gated channels to open)</u> . The potential generated is called Action potential.
<u>Summary</u>
<em>The specificity of these channels to certain ions while restricting others is a good illustration for Sumer to describe how a guard can control the movement of patrons in a controlled area.</em>