Changes

The cardiovascular system of snakes is similar to other non-crocodilian reptiles but is modified for their linear shape.

The cardiovascular system of snakes is similar to other non-crocodilian reptiles but is modified for their linear shape.

==Systemic venous return==

==Systemic venous return==

Snakes have both renal and hepatic portal circlations.  Jugulars are located anterior to the heart near the trachea and may be cannulated by a cutdown procedure.  The right jugular is larger than the left. Blood returns to the heart from the systemic circulation through the sinus venosus.  

Snakes have both renal and hepatic portal circluations.  Jugulars are located anterior to the heart near the trachea and may be cannulated by a cutdown procedure.  The right jugular is larger than the left. Blood returns to the heart from the systemic circulation through the sinus venosus.  

* Find out more about the snake [[Snake Respiratory System|respiratory system]].

* Find out more about the snake [[Snake Respiratory System|respiratory system]].

* Find out more about the reptile [[Lizard and Snake Haemopoietic System|haemopoietic system]].

* Find out more about the reptile [[Lizard and Snake Haemopoietic System|haemopoietic system]].

==Heart==

==Heart==

The position of the heart varies among [[:Category:Snake Species|species]] and, as there is no diaphragm, it is mobile within the [[Snake Musculoskeletal System|ribcage]].  Heart position varies slightly with its ecological niche and [[Snake Taxonomy|phylogenetic position]], and its mobility may facilitate the passage of relatively large prey (see [[Snake Feeding|snake feeding]]).  The heart has three chambers: right and left atria and one ventricle.  The right atrium receives deoxygenated blood from the systemic circulation and the left receives oxygenated blood from lungs via the left and right pulmonary veins.  The ventricle has internal ridges that enable a considerable functional separation between the oxygenated and deoxygenated blood.  It is divided into three subchambers: the cavum pulmonale, cavum venosum and cavum arteriosum.

The position of the heart varies among [[:Category:Snake Species|species]] and, as there is no diaphragm, it is mobile within the [[Snake Musculoskeletal System|ribcage]].  Heart position varies slightly with its ecological niche and [[Snake Taxonomy|phylogenetic position]], and its mobility may facilitate the passage of relatively large prey (see [[Snake Feeding|snake feeding]]).  The heart has three chambers: right and left atria and one ventricle.  The right atrium receives deoxygenated blood from the systemic circulation and the left receives oxygenated blood from lungs via the left and right pulmonary veins.  The ventricle has internal ridges that enable a considerable functional separation between the oxygenated and deoxygenated blood.  It is divided into three subchambers: the cavum pulmonale, cavum venosum and cavum arteriosum.