Changes

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.

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 spleen 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 spleen 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 - Reptile|lymphocyte]] is the T cell.

In lizards, the spleen is spindle-shaped and located just off the greater curvature of the stomach.

In lizards, the spleen is spindle-shaped and located just off the greater curvature of the stomach.

Located in the cervical region near the carotid arteries, it may have parathyroid glands attached and is often found adjacent to the ultimobranchial bodies. In snakes and lizards the thymus is lobulated.  

Located in the cervical region near the carotid arteries, it may have parathyroid glands attached and is often found adjacent to the ultimobranchial bodies. In snakes and lizards the thymus is lobulated.  

It produces T [[Lymphocytes|lymphocytes]] as in mammals. It may involute irreversibly under nutritional stress.

It produces T [[Lymphocytes - Reptile|lymphocytes]] as in mammals. It may involute irreversibly under nutritional stress.

==Other lymphoid deposits==

==Other lymphoid deposits==