Neurons are the cells in the nervous system
that conduct impulses called, action potentials
Like all cells, neurons have Na-K pumps - creates a charge gradient
Recall that pumps move substances up their concentration gradient (from low concentration to high) and require energy
K+ leaks out (due to concentration gradient), since it is positively chaged it leaves a net internal negativity
Neuron are electrically excitable due to several properties
Membrane proteins that allow for electrical excitability
Membrane proteins can be channels or gates
Some of these are voltage regulated channels that open (or close) when electrically stimulated
Some are chemically regulated channels that open or close when they bind to specific chemicals such as neurotransmitters