Somatic system contains sensory neurons from sense organs and motor neurons to muscles. Autonomic system contains sensory neurons from viscera and motor neurons to control glands, heart muscle, and smooth muscles of internal organs. Twelve pair of cranial nerves serve the head, neck, and face with a vagus nerve that branches to pharynx, larynx, and internal organs. Spinal nerves have a dorsal root conducting impulses inward from sensory neurons, and a ventral root containing axons of motor neurons. Somatic System Serves Skin and Muscles a.
Sensory neuron carries nerve impulse from dendrite to cell body in the dorsal root ganglion to axon.
Interneurons pass nerve impulse to the motor neuron in the gray matter of spinal cord. Motor neuron provides nerve impulse that leaves gray matter of spinal cord via motor neuron's axon in ventral root and stimulates effector. Autonomic System Serves Internal Organs a. Part of PNS that controls internal organs automatically and subconsciously. Innervates all internal organs. Uses two motor neurons and one ganglion for each impulse.