Final answer:
The process is known as an action potential, which depolarizes adjacent regions of a neuron's membrane but can only flow in one direction due to the refractory period behind the impulse.
Step-by-step explanation:
The process described is known as an action potential, which is a fundamental concept in the physiology of neurons and muscle cells. An action potential at one site on the membrane depolarizes an adjacent region of the membrane, triggering the same phenomenon at the second site. This electrical impulse can only flow in the forward direction because the portion of the membrane behind the impulse remains in a refractory period, during which it cannot readily initiate a new action potential.