The Cranial Nerves
The textbook discusses various divisions of the nervous system. You may want to add a description of the cranial nerves to your outline of the nervous system. Although the function of the cranial nerves is not different from that of the sensory and motor nerves in the spinal cord, they do not enter and leave the brain through the spinal cord. There are twelve cranial nerves, numbered 1 to 12 and ordered from the front to the back of the brain, that primarily transmit sensory information and control motor movements of the face and head. The twelve cranial nerves are:
1. Olfactory. A sensory nerve that transmits odor information from the olfactory receptors to the brain.
2. Optic. A sensory nerve that transmits information from the retina to the brain.
3. Oculomotor. A motor nerve that controls eye movements, the iris (and therefore pupil size), lens accommodation, and tear production.
4.Trochlear. A motor nerve that is also involved in controlling eye movements.
5. Trigeminal. A sensory and motor nerve that conveys somatosensory information from receptors in the face and head and controls muscles involved in chewing.
6.Abducens. Another motor nerve involved in controlling eye movements.
7. Facial. Conveys sensory information and controls motor and parasympathetic functions associated with facial muscles, taste, and the salivary glands.
8.Auditory-vestibular. A sensory nerve with two branches, one of which transmits information from the auditory receptors in the cochlea and the other conveys information concerning balance from the vestibular receptors in the inner ear.
9.Glossopharyngeal. This nerve conveys sensory information and controls motor and parasympathetic functions associated with the taste receptors, throat muscles, and salivary glands.
10. Vagus. Primarily transmits sensory information and controls autonomic functions of the internal organs in the thoracic and abdominal cavities.
11. Spinal accessory. A motor nerve that controls head and neck muscles.
12.Hypoglossal. A motor nerve that controls tongue and neck muscles.
Carlson, N. R. (1994). Physiology of behavior (5th ed.). Boston: Allyn and Bacon.