Cranial Nerves in Non-human Vertebrates
Human cranial nerves are nerves similar to those found in many other vertebrates. Cranial nerves XI and XII evolved in other species to amniotes (non-amphibian tetrapods), thus totaling twelve pairs. In some primitive cartilaginous fishes, such as the spiny dogfish or mud shark (Squalus acanthias), there is a terminal nerve numbered zero, since it exits the brain before the traditionally designated first cranial nerve. Because they exit from the brainstem as opposed to the spinal column, these are part of the central nervous system.
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Famous quotes containing the words nerves, non-human:
“Life is a series of diminishments. Each cessation of an activity either from choice or some other variety of infirmity is a death, a putting to final rest. Each loss, of friend or precious enemy, can be equated with the closing off of a room containing blocks of nerves ... and soon after the closing off the nerves atrophy and that part of oneself, in essence, drops away. The self is lightened, is held on earth by a gram less of mass and will.”
—Coleman Dowell (1925–1985)
“Almost like a god looking at her terribly out of the everlasting dark, she had felt the eyes of that horse; great glowing, fearsome eyes, arched with a question, and containing a white blade of light like a threat. What was his non-human question, and his uncanny threat? She didn’t know. He was some splendid demon, and she must worship him.”
—D.H. (David Herbert)