Answer
The twelve cranial nerves are part of the peripheral nervous system (PNS). They originate from the brain in th cranium, and pass out through foramina in the cranial bones. Each cranial nerve has a number, and a name. The numbers are Roman numerals (I-XII) and are given in numerical order from anterior to posterior. The name of the each nerve, for example, optic, glossopharyngeal, vagus, is based on the distribution of the nerve.
Work Step by Step
The following are the numbers, names and distribution of the cranial nerves:
CN I Olfactory nerve : Axons go to olfactory bulbs thence through olfactory tracts to olfactory
area in temporal lobes
CN II Optic : Axons conduct impulses for vision to optic chiasm, thence to primary visual
cortex of the occipital lobe and nuclei of midbrain and brainstem.
CN III Oculomotor : Controls muscles that move eyeballs and eyelids. . Nuclei in anterior of
midbrain
CN IV Trochlear; Motor nerves control eyeball muscles. Cell bodies in trochlear nucleus o f
midbrain
CN V Trigeminal : Mixed nerve with three branches (tri), that serve eye, maxilla and mandible. ;
cell bodies in mesencephalic nuclei
CN VI : Abducens. Cell bodies in abducens nucleus of the pons. controls eyeball
movement --abduction.
CN VII Facial This is a mixed nerve ;it serves the muscles and skin of face, as well as
scalp ; it also mediates, pain, touch, and proprioception. =; its nuclei are in
the pons and midbrain,
CN VIII Vestibulocochlear :: mediates balance and hearing; some axons from inner ear go to
cerebellum and: others go from pons and from spiral organ of Corti to
the pons, to the thalamus, to the temporal lobe
CN IX Glossopharyngeal: This nerve mediates taste, chemoreception; its sensory axons go to the
inferior and superior ganglia thence to the medulla ; motor neurons
from the otic
ganglion are associated swallowing, and secretion of saliva
C N X Vagus: The longest cranial nerve.; it wanders through neck, thorax, and
abdomen. Vagus cell bodies are in pons and medulla . this nerve is
concerned with perceptions of taste and satiety; it also involved with
respiratory and heart function.
CN XI Accessory: This nerve includes a cranial accessory, and a spinal accessory
branch. . Its sensory axons end up in the medulla ad its motor axons
descend to the spinal cord.
CN XII Hypoglossal; This motor nerves originates in the hypoglossal nucleus of
the medulla. It is concerned with speech and swallowing
