What connects sensory and motor neuron is the impulse called interneuron or connector neuron are connected by means of electrical impulse called synape from sensory to motor neuron.
preganglionic neuron
A neuron is called a inter-neuron because that specific neuron takes impulse from one neuron to a next neuron. For example your sensory neuron sends a impulse that you had felt a hot object. It goes through the spine to a inter-neuron to a motor neuron (this processes is called a reflex). Then the motor neuron tells your muscles in your hand to move
the motor unit
the motor unit
It is called a motor unit.
Motor unit = the single motor neuron and the multiple muscle fibers that it innervates.
Axon terminal
Interneurons(also called relay neuron, association neuron, connector neuron or local circuit neuron) are multipolar neurons that connects sensory neurons to motor neurons.
A relay neurone passes impulses from a sensory neurone to a motor neurone.
This is called a motor unit.
This type of nerve is called an efferent autonomic neuron.