macintosh
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Topics: 38
Posts: 178
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I would like to know, why the olfactory nerve is not myelinated by oligodendrocytes, when a closely positioned optic nerve is. Does it not arise from the brain. If so how does it come to be formed and eventually reach a position just inferior to the brain. Please explain as I am lost.
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| maoudoody
Forum Elite
Topics: 22
Posts: 401
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only the primary olfactory sensory neurons r not myelinated
myelination starts from the olfactory bulb
may be this due to the fact that these 1ry neurons r the only ones in the body that r continously replaced from stem cells present in the olfactory mucosa
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| macintosh
Forum Elite
Topics: 38
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Are the bulbs and the olfactory tract myelinated by schwann cells, because I haven,t heard of a multiple scslerosis patient with anosmia as one of its signs?
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| Jackofknives
Ipwnpoker.com
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myelination is not required to form a nerve or neural structure of any kind. The current paradigm is that, neurons, e.g. mitral cells, migrate enroute radial glia. No one really knows what triggers it.
CN I is unmyelinated throughout the entire pathway including the bulb, because mitral cells in the bulb give rise to the nerve. Review histo you should know that mitral cells are bipolar and if you understood that concept then you will know I am right on this one.
Olfactory nerve is an extension of the brain, however unmyelinated, hence not affected by MS.
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