Difference between revisions of "Snake Cardiovascular System"

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[[Image:Burmese python heart in situ.jpg|350px|thumb|right|'''[[Burmese Python|Burmese python]] heart''' ©RVC and its licensors, Peer Zwart and Fredric Frye. All rights reserved]]
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[[Image:Burmese python heart in situ.jpg|350px|thumb|right|'''[[Burmese Python|Burmese python]] heart''' (Copyright © RVC)]]
 
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.  
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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]].
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==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.
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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 and Digestion|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.
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Snakes can control arterial pressure reflexly, but this is diminished when the body temperature is outside the [[Preferred optimum temperature zone|preferred optimum temperature zone (POTZ)]].  Oxygen dissociation curves of snake [[Lizard and Snake Haemotology|blood]] are also influenced by temperature.
  
Snakes can control arterial pressure reflexly, but this is diminished when not within the [[POTZ]].  Oxygen dissociation curves of snake [[Lizard and Snake Haemotology|blood]] are also influenced by temperature.
 
 
==Systemic arteries==
 
==Systemic arteries==
 
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.   
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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 collection of blood, see [[Snake Blood Collection|snake blood collection]].'''
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'''For information on blood sample collection methods, see [[Snake Blood Collection|snake blood collection]].'''
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'''For information on reptile surgery, see [[Lizard and Snake Surgery|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.
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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.
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*'''For more information on reptile blood, see the relevant section on [[Lizard and Snake Haemotology|haematology]] or [[Lizard and Snake Biochemistry|biochemistry]].'''
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{{Learning
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|literature search = [http://www.cabdirect.org/search.html?q=od:(snakes)+AND+(ab:(cardiovascular)+OR+ab:(circulatory)+OR+ab:(heart)+OR+ab:(blood+vessel)+OR+ac:(cardi*))+AND+subject:(anatomy) Snake Cardiovascular Anatomy publications]
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*'''For more information on reptile blood, see [[Lizard and Snake Haemotology|lizard and snake haematology]] and [[Lizard and Snake Biochemistry|lizard and snake biochemistry]].'''
 
 
==References==
 
==References==
 
Mader, D.R. (2005). Reptile Medicine and Surgery. Saunders. pp. 47. ISBN 072169327X  
 
Mader, D.R. (2005). Reptile Medicine and Surgery. Saunders. pp. 47. ISBN 072169327X  
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==Webinars==
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<rss max="10" highlight="none">https://www.thewebinarvet.com/cardiology/webinars/feed</rss>
  
 
[[Category:Snake_Anatomy]]
 
[[Category:Snake_Anatomy]]
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[[Category:Cardiology Section]]

Latest revision as of 16:52, 3 January 2023


Burmese python heart (Copyright © RVC)

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

Systemic venous return

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.

Heart

The position of the heart varies among species and, as there is no diaphragm, it is mobile within the ribcage. Heart position varies slightly with its ecological niche and phylogenetic position, and its mobility may facilitate the passage of relatively large prey (see 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.

Snakes can control arterial pressure reflexly, but this is diminished when the body temperature is outside the preferred optimum temperature zone (POTZ). Oxygen dissociation curves of snake blood are also influenced by temperature.

Systemic arteries

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 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.

For information on blood sample collection methods, see snake blood collection.

For information on reptile surgery, see snake surgery.

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.


Snake Cardiovascular System Learning Resources
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Snake Cardiovascular Anatomy publications


References

Mader, D.R. (2005). Reptile Medicine and Surgery. Saunders. pp. 47. ISBN 072169327X



Webinars

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