| 翻訳と辞書 |
| olfactory nerve ： ウィキペディア英語版 |
olfactory nerve
The olfactory nerve ((ラテン語:nervus olfactorius)) is typically considered the first cranial nerve, or simply CN I. It contains the afferent nerve fibers of the olfactory receptor neurons, transmitting nerve impulses about odors to the central nervous system, where they are perceived by the sense of smell (olfaction). Derived from the embryonic nasal placode, the olfactory nerve is somewhat unique among cranial nerves because it is capable of some regeneration if damaged. The olfactory nerve is sensory in nature and originates on the olfactory mucosa in the upper part of the nasal cavity.〔Mcgraw Hill's Anatomy and Physiology Revealed〕 From the olfactory mucosa, the nerve (actually many small nerve fascicles) travels up through the cribriform plate of the ethmoid bone to reach the surface of the brain. Here the fascicles enter the olfactory bulb and synapse there; from the bulbs (one on each side) the olfactory information is transmitted into the brain via the olfactory tract. The fascicles of the olfactory nerve are not visible on a cadaver brain because they are severed upon removal.〔Saladin, Kenneth. "The Cranial Nerves." Anatomy and Physiology: The Unity of Form and Function. 6th ed. New York City: Mcgraw-Hill, 2012. 548.〕
==Structure==
The specialized olfactory receptor neurons of the olfactory nerve are located in the olfactory mucosa of the upper parts of the nasal cavity. The olfactory nerves consist of a collection of many sensory nerve fibers that extend from the olfactory epithelium to the olfactory bulb, passing through the many openings of the cribriform plate of the ethmoid bone, a sieve-like structure.
The sense of smell (olfaction) arises from the stimulation of receptors by small molecules in inspired air of varying spatial, chemical, and electrical properties that reach the nasal epithelium in the nasal cavity during inhalation. These stimulants are transduced into electrical activity in the olfactory neurons, which then transmit these impulses to the olfactory bulb and from there to the rest of the central nervous system via the olfactory tract.
The olfactory nerve is the shortest of the twelve cranial nerves and, similar to the optic nerve, does not emanate from the brainstem.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「olfactory nerve」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|