Human Brain Mapping - Visible Anatomy - Cranial Nerves

Cranial Nerves

• Many neurons connect to the brain on one end, with the other end connected to another neuron, with the outside (the brain) junction located within the spinal column. Other neurons bundles which are labeled Cranial nerves, connect to the brain on one end, and to locations outside the brain on the other, without having a junction inside the spinal column. Cranial nerves are actually huge collections of vast numbers of individual neurons that have found common routes though the body. They branch several times into smaller bundles which eventually reach many endpoints. With one exception, the optic nerve, they are considered to part of the peripheral nervous system.
• Cranial nerve zero Controversial but commonly found nerve which is perhaps vestigial or may be somehow related to the sensing of pheromones.
• Olfactory nerve (cranial nerve 1) Smell. See also: olfactory receptor neurons
• Optic nerve (cranial nerve 2) Sight. See also: retinal ganglion cell
• Oculomotor nerve (cranial nerve 3) Eye movement (except rotation), including constriction of the pupil and maintaining an open eyelid.
• Trochlear nerve (cranial nerve 4) controls most eye rotation (with head still, look up, down, left, right).
• Trigeminal nerve (cranial nerve 5) provides sensation from the face and certain motor functions such as biting and chewing.
• Abducens nerve (cranial nerve 6) controls certain eye rotation. (It controls the lateral rectus muscle used to bring the pupil away from the midline of the body)
• Facial nerve (cranial nerve 7) controls the muscles of facial expression, and taste sensations from the tongue and oral cavity.
• Vestibulocochlear nerve (cranial nerve 8) transmits sound and equilibrium (balance) information from the inner ear.
• Glossopharyngeal nerve (cranial nerve 9) primarily receives sensation from the throat, tonsils, part of the tongue, heart, and stomach. Also sends information to larynx and pharynx to facilitate swallowing.
• Vagus nerve (cranial nerve 10) sends output to the intestines, innervates the heart, receives taste information, deep/crude touch, pain, temperature of outer ear, larynx (name is akin to vagrant, i.e. wandering...)
• Accessory nerve (Cranial nerve 11) controls specific muscles of the shoulder and neck. Modern descriptions often consider the cranial component part of the traditional accessory nerve to be more properly classified as part of the vagus nerve, leaving what is left to be called the spinal accessory nerve.
• Hypoglossal nerve (Cranial nerve 12) leads to muscles of the tongue.