Cranial Nerves: Type and Function
| Cranial Nerve (Name) | Type of Impulse | Function |
|---|---|---|
| I (olfactory) | Sensory | Carries smell impulses from nasal mucous membrane to brain |
| II (optic) | Sensory | Carries visual impulses from eye to brain |
| III (oculomotor) | Motor | Contracts eye muscles to control eye movements (inferior lateral, medial, and superior), constricts pupils, and elevates eyelids |
| IV (trochlear) | Motor | Contracts one eye muscle to control inferomedial eye movement |
| V (trigeminal) | Sensory Motor | Carries sensory impulses of pain, touch, and temperature from the face to the brain Influences clenching and lateral jaw movements (biting, chewing) |
| VI (abducens) | Motor | Controls lateral eye movements |
| VII (facial) | Sensory Motor | Contains sensory fibers for taste on anterior two-thirds of tongue and stimulates secretions from salivary glands (submaxillary and sublingual) and tears from lacrimal glands Supplies the facial muscles and affects facial expressions (smiling, frowning, closing eyes) |
| VIII (acoustic, vestibulocochlear) | Sensory | Contains sensory fibers for hearing and balance |
| IX (glossopharyngeal) | Sensory Motor | Contains sensory fibers for taste on posterior third of tongue and sensory fibers of the pharynx that result in the "gag reflex" when stimulated Provides secretory fibers to the parotid salivary glands; promotes swallowing movements |
| X (vagus) | Sensory Motor | Carries sensations from the throat, larynx, heart, lungs, bronchi, gastrointestinal tract, and abdominal viscera Promotes swallowing, talking, and production of digestive juices |
| XI (spinal accessory) | Motor | Innervates neck muscles (sternocleidomastoid and trapezius) that promote movement of the shoulders and head rotation. Also promotes some movement of the larynx |
| XII (hypoglossal) | Motor | Innervates tongue muscles that promote the movement of food and talking |