Changes

==Oral cavity==

==Oral cavity==

[[Image:Open_mouth.jpg|200px|thumb|right|'''Sheathed tongue of a bullsnake''' - (Copyright © RVC)]]  

[[Image:Open_mouth.jpg|200px|thumb|right|'''Sheathed tongue of a bullsnake''' - (Copyright © RVC)]]  

The mouth of a snake can open widely by the independent movement of the jaws to accommodate relatively [[Snake Feeding|large prey]].  The mucous salivary glands moisten the mouth, lubricate prey, aid digestion and excrete salt.  Venom glands that produce toxins to kill prey are modified salivary glands.  The sheathed tongue lies in a diverticulum on the floor of the mouth ventral to the glottis.  It functions for [[Snake Special Senses|vomeronasal chemoreception]] and plays no role in swallowing, during which is is retracted into the sheath.  Snakes that lose their tongues may not feed.  The surface epithelial layer or the snake's tongue is periodically [[Snake Shedding|shed]] intact and is often seen in the water bowl.  The oral mucosa of snakes is paler than that of mammals since the PCV may be about half to two thirds that of mammals.

The mouth of a snake can open widely by the independent movement of the jaws to accommodate relatively [[Snake Feeding and Digestion|large prey]].  The mucous salivary glands moisten the mouth, lubricate prey, aid digestion and excrete salt.  Venom glands that produce toxins to kill prey are modified salivary glands.  The sheathed tongue lies in a diverticulum on the floor of the mouth ventral to the glottis.  It functions for [[Snake Special Senses|vomeronasal chemoreception]] and plays no role in swallowing, during which is is retracted into the sheath.  Snakes that lose their tongues may not feed.  The surface epithelial layer or the snake's tongue is periodically [[Snake Shedding|shed]] intact and is often seen in the water bowl.  The oral mucosa of snakes is paler than that of mammals since the PCV may be about half to two thirds that of mammals.

==Oesophagus, stomach and intestines==

==Oesophagus, stomach and intestines==

The oesophagus is distensible to accommodate relatively large prey (for a list of diets, see [[Snake Diet|snake feeding]].  The cranial oesophagus is thinly muscled.  At the level of the [[Snake Cardiovascular System|heart]], the oesophagus passes through the vascular ring formed by the left and right aortae.  It possesses longitudinal folds and is covered with a columnar ciliated epithelium.  The oesophagus terminates as the [[Snake Cardiovascular System|cardiac sphincter]].  The thick-walled, spindle-shaped stomach is muscular and distensible.  The small intestine is relatively uncoiled but has several short transverse loops tightly enveloped by dorsal mesentery.  It empties into the colon that may store faeces. The large intestine is relatively wide and is separated from the cloaca by a distinct fold.  A small caecum projects from the proximal colon in Boidae.

The oesophagus is distensible to accommodate relatively large prey (for a list of diets, see [[Snake Diet|snake diet]].  The cranial oesophagus is thinly muscled.  At the level of the [[Snake Cardiovascular System|heart]], the oesophagus passes through the vascular ring formed by the left and right aortae.  It possesses longitudinal folds and is covered with a columnar ciliated epithelium.  The oesophagus terminates as the [[Snake Cardiovascular System|cardiac sphincter]].  The thick-walled, spindle-shaped stomach is muscular and distensible.  The small intestine is relatively uncoiled but has several short transverse loops tightly enveloped by dorsal mesentery.  It empties into the colon that may store faeces. The large intestine is relatively wide and is separated from the cloaca by a distinct fold.  A small caecum projects from the proximal colon in Boidae.

* For more information on snake digestion, see [[Snake Feeding|snake digestion]].

* For more information on snake digestion, see [[Snake Feeding and Digestion|snake digestion]].

* Learn about snake excretion [[Lizard and Snake Excretion|here]].

* Learn about snake excretion [[Lizard and Snake Excretion|here]].