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In anatomy, a nasal concha (or turbinate) is a long, narrow and curled bone shelf (shaped like an elongated sea-shell) that protrudes into the breathing passage of the nose. Turbinate bone refers to any of the scrolled spongy bones of the nasal passages in vertebrates. 〔(''Anatomy of the Human Body'' ) Gray, Henry (1918) The Nasal Cavity.〕 In humans, the turbinates divide the nasal airway into 4 groove-like air passages, and are responsible for forcing inhaled air to flow in a steady, regular pattern around the largest possible surface of cilia and climate-controlling tissue. A rapidly dilating arteriolar circulation to these bones may lead to a sharp increase in the pressure within, in response to acute cooling of the body core - the pain from this pressure is often referred to as "brain freeze", and is frequently associated with the rapid consumption of ice cream. ==Structure== Turbinates are composed of pseudostratified columnar, ciliated respiratory epithelium with a thick, vascular, and erectile glandular tissue layer. 〔(Turbinate Dysfunction: Focus on the role of the inferior turbinates in nasal airway obstruction. ) S.S. Reddy, et al. ''Grand Rounds Presentation, UTMB, Dept. of Otolaryngology''〕 The turbinates are located laterally in the nasal cavities, curling medially and downward into the nasal airway. Each pair is composed of one turbinate in either side of the nasal cavity, divided by the septum.〔 The ''superior turbinates'' are smaller structures, connected to the middle turbinates by nerve-endings, and serve to protect the olfactory bulb. The openings to the posterior ethmoidal sinuses exist under the superior meatus.〔 The ''middle turbinates'' are smaller. In humans, they are usually as long as the little finger. They project downwards over the openings of the maxillary and anterior and middle ethmoid sinuses, and act as buffers to protect the sinuses from coming in direct contact with pressurized nasal airflow. Most inhaled airflow travels between the inferior turbinate and the middle meatus.〔 The ''inferior turbinates'' are the largest turbinates, and can be as long as the index finger in humans, and are responsible for the majority of airflow direction, humidification, heating, and filtering of air inhaled through the nose.〔 The ''inferior turbinates'' are graded 1-4 based on the inferior turbinate classification system in which the total amount of the airway space that the inferior turbinate takes up is estimated. Grade 1 is 0-25% of the airway, grade 2 is 26-50% of the airway, grade 3 is 51-75% of the airway and grade 4 is 76-100% of the airway.〔Camacho, M., Zaghi, S., Certal, V., Abdullatif, J., Means, C., Acevedo, J., Liu, S., Brietzke, S. E., Kushida, C. A. and Capasso, R. (2014), Inferior Turbinate classification system, grades 1 to 4: Development and validation study. The Laryngoscope. doi: 10.1002/lary.24923 〕 There is sometimes a pair of ''supreme turbinates'' superior to the superior turbinates. When present, these usually take the form of a small crest. 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「Nasal concha」の詳細全文を読む スポンサード リンク
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