A motor neuron is basically a neuron that begins within the central nervous system and then extends into the peripheral nervous system. And it basically carries an electric signal to some type of target cell. Usually the target could be an organ. It could be a gland, it could be a muscle and so forth. And because that target is usually known as an effector so the organ that our motor neuron is trying to send that signal to is known as our effector. And that's exactly why sometimes the motor neurons are also known as efferent neurons.