The sympathetic division responds to stress and the parasympathetic division calms the nerves. There are many nerves in the brain that these divisions must communicate with, but knowing them can be helpful. They can be classified based on motor sense or both. The sensory nerves are the olfactory nerve which processes visual stimuli, the optic nerve which processes visual stimuli, the auditory nerve which processes audio inputs. The motor nerves are the Oculomotor which controls 4/6 eye muscles, the Trochlear nerve controls 1/6 eye muscles, the Abducens controls some eye movements, the Spinal accessory nerve moves the head and shoulders, the Hypoglossal nerve allows you to swallow and speak. Some nerves can be both sensory and motor, there are only three: the facial nerve which moves the facial muscles, the glossopharyngeal nerve which moves the tongue and pharynx, the vagus nerve which controls digestion of the heart.