Normally, the coordinated action of the muscles of the stomach and small intestine propels the food from the stomach, through the small intestine and into the colon. This muscular action also sweeps bacteria out of the small intestine and limits the numbers of bacteria in the small intestine.
The term 'motor neuron' is usually restricted to the efferent neurons that actually innervate muscles (the lower motor neurons). A single motor neuron may innervate many muscle fibres and a muscle fibre can undergo many action potentials in the time taken for a single muscle twitch.
motor, n pertaining to a muscle, nerve, or center that produces or affects movement. motor neuron, n one of the various efferent nerve cells that transmit nerve impulses from the brain or from the spinal cord to muscular or glandular tissue. the entity consisting of the lower motor neuron, motor end-plate, and muscle fibers supplied by the end-plate. The final motor activity resulting from a sequence of stimulations to the lower motor neuron is considered a function of the motor unit.