Changes

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[[Image:718099 - external_nares_ed_copy.jpg|200px|thumb|right|'''External nares''' ©RVC and its licensors, Peer Zwart and Fredric Frye. All rights reserved]]

[[Image:718099 - external_nares_ed_copy.jpg|200px|thumb|right|'''External nares''' (Copyright © RVC)]]

The respiratory tract of snakes consists of external nares, nasal cavity, internal nares, glottis, trachea, bronchi, lung(s) and air sac. There is no diaphragm.  The external nares communicate with the internal nares through the nasal cavity.  The internal nares lie in the roof of the oral cavity and communicate directly with the glottis when the mouth is closed. The glottis lies posterior to the tongue and is not difficult to visualise, making intubation for [[Lizard and Snake Anaesthesia|anaesthesia]] relatively easy.  During the feeding process, the glottis is able to move laterally to facilitate respiration while ingesting large prey items, a process which may take considerable time.

The respiratory tract of snakes consists of external nares, nasal cavity, internal nares, glottis, trachea, bronchi, lung(s) and air sac. There is no diaphragm.  The external nares communicate with the internal nares through the nasal cavity.  The internal nares lie in the roof of the oral cavity and communicate directly with the glottis when the mouth is closed. The glottis lies posterior to the tongue and is not difficult to visualise, making intubation for [[Lizard and Snake Anaesthesia|anaesthesia]] relatively easy.  During the feeding process, the glottis is able to move laterally to facilitate respiration while ingesting large prey items, a process which may take considerable time.

*Also, see [[Snake Physical Examination|snake physical examination]].

*Also, see [[Snake Physical Examination|snake physical examination]].

==Trachea==

==Trachea==

[[Image:Glottis_&_int_nares_copy.jpg|200px|thumb|right|'''Internal nares and glottis''' ©RVC and its licensors, Peer Zwart and Fredric Frye. All rights reserved]]

[[Image:Glottis_&_int_nares_copy.jpg|200px|thumb|right|'''Internal nares and glottis''' (Copyright © RVC)]]

The trachea has incomplete cartilaginous rings. The ventral portion is rigid cartilage while the dorsal fourth is membranous. The trachea enters the lung at a level near the base of the heart. Some species of snakes have a unique saccular diverticulum of open tracheal rings that acts for hissing or as a tracheal lung for gas exchange when gastric contents preclude normal pulmonary function.  

The trachea has incomplete cartilaginous rings. The ventral portion is rigid cartilage while the dorsal fourth is membranous. The trachea enters the lung at a level near the base of the heart. Some species of snakes have a unique saccular diverticulum of open tracheal rings that acts for hissing or as a tracheal lung for gas exchange when gastric contents preclude normal pulmonary function.  

==Lungs==

==Lungs==