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Spleen - Anatomy & Physiology (view source)
Revision as of 15:15, 17 July 2008
, 15:15, 17 July 2008no edit summary
|subtext1 =SECONDARY LYMPHOID TISSUE (Ant & Phys)
|subtext1 =SECONDARY LYMPHOID TISSUE (Ant & Phys)
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The spleen is a major lymphoid and blood filtration organ and is located in the left cranial abdomen. It is responsible for storing and removing erythrocytes from the blood as well as antigen surveillance of the blood and antibody production.
==Development==
==Development==
<p>The spleen develops in association with the digestive system in the dorsal mesogastrium, and as the stomach rotates during development the spleen comes to occupy the left cranial abdomen. Haematopoietic cells in the spleen are derived from the AGM (aorta-gonad-mesonephros) and yolk sac and as the primary lymphoid organs become established it becomes populated with T and B lymphocytes.</p>
<p>The spleen develops in association with the digestive system in the dorsal mesogastrium, and as the stomach rotates during development the spleen comes to occupy the left cranial abdomen. Haematopoietic cells in the spleen are derived from the AGM (aorta-gonad-mesonephros) and yolk sac and as the primary lymphoid organs become established it becomes populated with T and B lymphocytes.</p>
===Innervation===
===Innervation===
Innervation is purely sympathetic[[LH References - Anatomy & Physiology#Nance|<sup>Ref:Nance</sup>]] and nerve fibres travel with the artery into the spleen.
Innervation is purely sympathetic[[LH References - Anatomy & Physiology#Nance|<sup>Ref:Nance</sup>]] and nerve fibres travel with the artery into the spleen.
===Histology===
===Histology===
==Functions==
==Functions==
<p>The spleen has a number of functions:
<p>The spleen has a number of functions:
<p>Blood flows through the marginal sinus meaning that most antigens present in the blood come into contact with the B cells and dendritic cells in the spleen. Dendritic cells in the marginal sinus and red pulp take up antigens from the blood and transport them to the primary follicles in the white pulp. If the antigen activates the B lymphocytes then a germinal centre will form in the primary follicle and this is called a splenic nodule. Antibody producing cells then migrate to the red pulp and marginal zone.</p>
<p>Blood flows through the marginal sinus meaning that most antigens present in the blood come into contact with the B cells and dendritic cells in the spleen. Dendritic cells in the marginal sinus and red pulp take up antigens from the blood and transport them to the primary follicles in the white pulp. If the antigen activates the B lymphocytes then a germinal centre will form in the primary follicle and this is called a splenic nodule. Antibody producing cells then migrate to the red pulp and marginal zone.</p>
<p>Following splenectomy this doesn’t occur and animals are predisposed to septicaemia and infection with blood protozoa.</p>
<p>Following splenectomy this doesn’t occur and animals are predisposed to septicaemia and infection with blood protozoa.</p>
==In pathology==
==In pathology==
[[Lymphoreticular/Haemotopoietic System - Spleen|See here]]
[[Lymphoreticular/Haemotopoietic System - Spleen|See here]]