- cranial nerve
Anat.any of the nerves arising from the brainstem and exiting to the periphery of the head through skull openings, including 10 pairs in fish and amphibians and 12 pairs in reptiles, birds, and mammals: in humans, these are the abducens nerve, accessory nerve, auditory nerve, facial nerve, glossopharyngeal nerve, hypoglossal nerve, oculomotor nerve, olfactory nerve, optic nerve, trigeminal nerve, trochlear nerve, and vagus nerve.[1830-40]
* * *▪ anatomyin vertebrates, any of the paired nerves of the peripheral nervous system that connect the muscles and sense organs of the head and thoracic region directly to the brain. In higher vertebrates (reptiles, birds, mammals) there are 12 pairs of cranial nerves: olfactory (I), optic (II), oculomotor (III), trochlear (IV), trigeminal (V), abducent (VI), facial (facial nerve) (VII), vestibulocochlear (VIII), glossopharyngeal (IX), vagus (vagus nerve) (X), accessory (XI), and hypoglossal (XII). Lower vertebrates (fishes, amphibians) have 10 pairs.Cranial nerves are made up of motor neurons (neuron), sensory neurons, or both. The vagus (vagus nerve) nerve is one of the most important; it extends to many of the organs in the chest and upper abdomen.
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