The trigeminal nerve (cranial nerve V) is responsible for facial sensation and motor functions, such as biting and chewing. The trigeminal nerve has three major branches (hence: tri-): the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3). The opthalmic and maxillary nerves are purely sensory, and the mandibular nerve has both sensory and motor functions. VI provides sensation to the forehead, upper eyelids, and the bridge and tip of the nose. V2 provides sensation lateral to the eyelids, the cheeks, nostrils, and upper lip. V3 provides sensation to the lower lip, chin, skin over the jaw, and pre-auricular area.

Cranial nerves VII and IX supply taste sensation to the tongue. Cranal nerve VII (facial) supplies taste to the anterior two-thirds of the tongue and cranial nerve IX (glossopharyngeal) supplies somatosensation and taste to the posterior one-third of the tongue.

Cranial nerve V (trigeminal) has 3 branches: ophthalmic, maxillary, and mandibular. Each of these branches have their own branches. The maxillary branch has 3 sub-branches named zygomaticofacial, zygomaticotemporal, and infraorbital. The mandibular branch has 3 sub-branches named auriculotemporal, buccal, and mental. The ophthamic branch has 5 sub-branches named supraorbital, supratrochlear, infraorbital, lacrimal, and external nasal.

The glossopharyngeal cranial nerve functions in supplying visceral and somatic afferent sensation from the carotid body, carotid sinus, posterior one-third of the tongue, palatine tonsils, oropharynx, mucosa of the middle ear, and pharyngotympanic tube. It also supplies taste from the posterior one-third of the tongue and visceral efferent function to parotid salivary gland.

The four cranial nerves the have sensory and motor function are cranial nerve V (trigeminal), VII (facial), IX (glossopharyngeal), and X (vagus).

Cranial nerve XII, the hypoglossal nerve, is responsible for controlling muscles that move the tongue. The vestibulocochlear nerve is responsible for sound and balance. The abducens and trochlear are responsible for controlling extraocular muscles. The optic nerve conveys information from the photoreceptor cells of the retina of the eye. 

Taste is unique and is controlled by the facial, glossopharyngeal, and vagus cranial nerves. This can be further explained in which facial controls the anterior two-thirds of the tongue, glossopharyngeal controls the posterior one-third, and vagus innervates taste in the pharynx.

Parasympathetic nerves are autonomic branches of the peripheral nervous system (PNS). These arise from some cranial nerves (that participate in cranial nuclei), the vagus nerve (although a cranial nerve, these fibers doe not participate in cranial ganglia and their parasympathetic action is directed to the thoracic cavity), and pelvic splanchnic efferent preganglionic nerve bodies. 

The preganglionic parasympathetic nerves of CN III, CN VII, and CN IX arise from nuclei in the CNS. These fibers go on to synapse at one of four parasympathetic ganglia: ciliary, pterygopalatine, submandibular, or otic and provide parasympathetic function to the head and neck.

The autonomic nervous system can be divided into the parasympathetic system and the sympathetic system. The autonomic system is responsible for regulating the body's unconscious activity. The sympathetic system is responsible for stimulating activities associated with "fight or flight," and includes mydriasis (dilation of the pupil). The parasympathetic response is responsible for "rest and digest," and includes mucus secretion, salivation, lacrimation, urination, digestion, and defecation. 

Though all of these nerves are involved with the eye, only one of them is involved with vision. The optic nerve (cranial nerve II) has a sensory function, allowing us to see. The oculomotor nerve (cranial nerve III) has a motor function, allowing eyelid and eyeball movement. The trochlear nerve (cranial nerve IV) also has a motor function, allowing the eye to turn downward and laterally. Lastly, the abducens nerve (cranial nerve VI) also has a motor function, allowing the eye to turn laterally.