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[[Image:Lizard_renal_diagram.gif|400px|thumb|right|'''Lizard renal portal system''' (© RVC and its licensors, Sean Bobbit, Sue Evans, Andrew Devare and Claire Moore. All rights reserved)]]

[[Image:Lizard_renal_diagram.gif|400px|thumb|right|'''Lizard renal portal system''' (Copyright © RVC)]]

Reptiles have a renal portal system where venous return from the tail and hindlimbs may be filtered through the kidneys to bathe the renal tubules. Of surgical importance is the large ventral abdominal vein that lies along the inner surface of the abdominal wall in the midline.

 

Lizards have a three chambered heart with left and right atria and a single ventricle - the interventricular septum is only partially complete but serves to channel deoxygenated blood to the pulmonary trunk and oxygenated blood to the circulation. In addition the atria contract at different times, thus directing the flow of blood between the sponge-like arranged muscle bundles which form the major part of the ventricle.There are paired left and right aortic arches which join caudal to the heart to form a single dorsal aorta.

==The renal portal system==

==The renal portal system==

Venous return from the tail and hindlimbs may be filtered through the kidney or liver. When filtered through the kidney the blood bathes the renal tubules. Theoretically this may affect the pharmokinetics of drugs that are excreted by tubular secretion. In practice this may not be important. It should not affect drugs that are secreted by glomerular filtration.

Reptiles have a renal portal system where venous return from the tail and hindlimbs may be filtered through the kidneys to bathe the renal tubules. Venous return may also be filtered through the liver. 

 

* The [[Lizard Injection|injection]] of drugs that are cleared via tubular excretion into the caudal half of the body could result in lower than anticipated serum concentration because of their excretion in the urine before entering the systemic circulation. This could potentially result in increased renal toxicity when using nephrotoxic drugs (eg. aminoglycosides); however the results of limited pharmacokinetic studies suggest that the renal portal system has less effect on drug uptake and distribution than previously thought. Furthermore, shunts exist that carry blood directly from the renal portal system to the postcava, bypassing the renal parenchyma.

 

 

* Of [[Lizard and Snake Surgery|surgical]] importance is the large [[Ventral abdominal vein|ventral abdominal vein]] that lies along the inner surface of the abdominal wall in the midline. It must be avoided in a celiotomy incision, for example by using a paramedian incision. It should also be protected with saline solution-moistened gauze and it can be ligated without clinical effect.

 

* Venipuncture can be done with the ventral caudal vein in species that do not undergo tail [[Autotomy|autotomy]], with the axillary venous plexus or with the jugular vein.

 

 

 

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

==Heart==

==References==

Lizards have a three chambered heart with left and right atria and a single ventricle - the interventricular septum is only partially complete but serves to channel deoxygenated blood to the pulmonary trunk and oxygenated blood to the circulation. In addition the atria contract at different times, thus directing the flow of blood between the sponge-like arranged muscle bundles which form the major part of the ventricle.There are paired left and right aortic arches which join caudal to the heart to form a single dorsal aorta.

* Mader, D.R. (2005). ''Reptile Medicine and Surgery''. Saunders. pp. 1264. ISBN 072169327X