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Lizard and Snake Haemopoietic System (view source)
Revision as of 14:35, 22 April 2010
, 14:35, 22 April 2010→Spleen
==Spleen==
==Spleen==
In reptiles, the spleen lies in the dorsal mesentery, close to the stomach and pancreas, as in mammals. However, the splee-to-bodyweight ratio is the smallest of any vertebrates except birds (Tanaka, 1998). In some species, it may be a separate organ but found combined with the pancreas as splenopancreas (e.g. some snakes, such as the milk snake). In boid snakes, the spleen is multilobulate.
In reptiles, the spleen lies in the dorsal mesentery, close to the stomach and pancreas, as in mammals. However, the spleen-to-bodyweight ratio is the smallest of any vertebrates except birds (Tanaka, 1998). In some species, it may be a separate organ but found combined with the pancreas as splenopancreas (e.g. some snakes, such as the milk snake). In boid snakes, the spleen is multilobulate.
The splenic artery, arrising from the coeliac artery, supplies the sleen with blood. It is composed of mesenchymal tissue enclosed in a fibrous capsule. The white pulp is well developed and the red pulp is absent in snakes but present in other reptiles. Arteriovenous connections are generally of the closed type, unlike the more common open type seen in mammals. It appears to be primarily lymphopoietic and no blood storage capacity has been reported in reptiles. Futhermore, the spleen is a site of possible extramedullary haemopoiesis, as is the liver. The predominant splenic [[Lymphocytes|lymphocyte]] is the T cell.
The splenic artery, arrising from the coeliac artery, supplies the sleen with blood. It is composed of mesenchymal tissue enclosed in a fibrous capsule. The white pulp is well developed and the red pulp is absent in snakes but present in other reptiles. Arteriovenous connections are generally of the closed type, unlike the more common open type seen in mammals. It appears to be primarily lymphopoietic and no blood storage capacity has been reported in reptiles. Futhermore, the spleen is a site of possible extramedullary haemopoiesis, as is the liver. The predominant splenic [[Lymphocytes|lymphocyte]] is the T cell.