Changes

There are two aortae that leave the heart - the right aorta exits from the left side of the ventricle and the left aorta from the right side.  The aortae join caudal to the heart to form the abdominal aorta that extends caudally through the coelomic cavity.  The left systemic arch is larger than the right, the opposite to most tetrapods.   

There are two aortae that leave the heart - the right aorta exits from the left side of the ventricle and the left aorta from the right side.  The aortae join caudal to the heart to form the abdominal aorta that extends caudally through the coelomic cavity.  The left systemic arch is larger than the right, the opposite to most tetrapods.   

Carotids extend cranially from the heart and adjacent to the trachea.  The jugulars may be easily [[Lizard and Snake Surgery|cannulated]] by a cutdown for placement of an IV catheter.   

Carotids extend cranially from the heart and adjacent to the trachea.  The jugulars may be easily cannulated by a cutdown for placement of an IV catheter.   

*Sites to collect blood from a snake include a ventral tail vein and cannulated jugular vein, and via cardiocentesis.   

*Sites to collect blood from a snake include a ventral tail vein and cannulated jugular vein, and via cardiocentesis.   

'''For information on reptile surgery, see [[Lizard and Snake Surgery|lizard and snake surgery]].'''

'''For information on reptile surgery, see [[Lizard and Snake Surgery|lizard and snake surgery]].'''

==Haemocrit==

==Haemocrit==

The normal packed cell volume of a snake ranges between 20% and 30%.  The blood volume (based on the black ratsnake, ''Elaphe'' sp.) is equivalent to approximately 6% of the animal's body weight.

The normal packed cell volume of a snake ranges between 20% and 30%.  The blood volume (based on the black ratsnake, ''Elaphe'' sp.) is equivalent to approximately 6% of the animal's body weight.