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|[[Image:LH_Canine_labelled_lateral_abdominal_organs_radiograph.jpg|150px]]

|[[Image:LH_Canine_labelled_lateral_abdominal_organs_radiograph.jpg|200px]]

|[[Image:LH_Canine_labelled_ventrodorsal_abdominal_organs_radiograph.jpg|150px]]

|[[Image:LH_Canine_labelled_ventrodorsal_abdominal_organs_radiograph.jpg|200px]]

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!colspan="2"|<center>Location canine radiograph</center>

!colspan="2"|<center>Location canine radiograph</center>

|colspan="2"|<center>^{©Nottingham Uni 2008}</center>

|colspan="2"|<center>^{©Nottingham Uni 2008}</center>

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|-

|colspan="2"|<center>[[Image:LH Spleen Gross Histology.jpg|150px]]</center>

|colspan="2"|<center>[[Image:LH Spleen Histology.jpg|200px]]</center>

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|colspan="2"|<center>'''Gross histological view'''</center>

|colspan="2"|<center>'''Histological view'''</center>

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|colspan="2"|<center>^{©Nottingham Uni 2008}</center>

|colspan="2"|<center>^{©Nottingham Uni 2008}</center>

<p> The parenchyma is supported by a fine mesh of reticular fibres and is divided into two types of tissue, the red and the white pulp, which are separated by the marginal sinus.</p>

<p> The parenchyma is supported by a fine mesh of reticular fibres and is divided into two types of tissue, the red and the white pulp, which are separated by the marginal sinus.</p>

===Red Pulp===

===Red Pulp===

<p>The red pulp makes up the majority of the spleen and is composed of a network of cell cords in series with vascular sinuses. The splenic cords contain [[Macrophages|macrophages]], [[B cell differentiation#Plasma cells|plasma cells]], [[Lymphocytes - Introduction|lymphocytes]] and other mature blood cells e.g. [[Granulocytes|granulocytes]] and [[Erythrocytes|erythrocytes]].  While the vascular sinuses are wide vascular channels lined with endothelial cells. Blood cells and fluid can pass into the splenic cords through fenestrations in the sinus walls. </p>

<p>The red pulp makes up the majority of the spleen and is composed of a network of cell cords in series with vascular sinuses. The splenic cords contain [[Macrophages|macrophages]], [[B cell differentiation#Plasma cells|plasma cells]], [[Lymphocytes - Introduction|lymphocytes]] and other mature blood cells e.g. [[Blood Cells - Overview|granulocytes]] and [[Erythrocytes|erythrocytes]].  While the vascular sinuses are wide vascular channels lined with endothelial cells. Blood cells and fluid can pass into the splenic cords through fenestrations in the sinus walls. </p>

 

===White Pulp===

===White Pulp===

<p>White pulp is organised in relation to the splenic arterioles and consists of discrete lymphoid tissue surrounding a central arteriole. There is a sheath of [[Lymphocytes#T cells|T cells]] directly around the arteriole, the periarteriolar lymphoid sheath (PALS), which is surrounded by a marginal sinus, and then a zone of [[Lymphocytes#B cells|B cells]] and [[Macrophages|macrophages]] (the marginal zone). B cell follicles are associated with the marginal zone and expand and develop germinal centres after antigen activation. The marginal sinuses are linked to the red pulp sinuses. </p><p>White pulp stains basophilic in a H&E stain</p>

<p>White pulp is organised in relation to the splenic arterioles and consists of discrete lymphoid tissue surrounding a central arteriole. There is a sheath of [[Lymphocytes#T cells|T cells]] directly around the arteriole, the periarteriolar lymphoid sheath (PALS), which is surrounded by a marginal sinus, and then a zone of [[Lymphocytes#B cells|B cells]] and [[Macrophages|macrophages]] (the marginal zone). B cell follicles are associated with the marginal zone and expand and develop germinal centres after antigen activation. The marginal sinuses are linked to the red pulp sinuses. </p><p>White pulp stains basophilic in a H&E stain</p>

**Is flat and oblong shaped

**Is flat and oblong shaped

*Horses

*Horses

**Lies under the last three [[Ribs and Sternum: Anatomy and Physiology|ribs]]. Dorsally it is broad but narrows as it extends cranially and ventrally

**Lies under the last three [[Ribs and Sternum - Anatomy & Physiology|ribs]]. Dorsally it is broad but narrows as it extends cranially and ventrally

**On rectal palpation it is located against the body wall and feels smooth with a sharp border

**On rectal palpation it is located against the body wall and feels smooth with a sharp border

*Pigs

*Pigs

**Elongated and strap-like under the last few [[Ribs and Sternum: Anatomy and Physiology|ribs]]

**Elongated and strap-like under the last few [[Ribs and Sternum - Anatomy & Physiology|ribs]]

*Birds ([[Media:Avian Liver and Spleen.jpg|Picture here]])

*Birds ([[Media:Avian Liver and Spleen.jpg|Picture here]])

**Lies alongside, to the right, of the [[Proventriculus - Anatomy & Physiology|proventriculus]] and is found caudodorsally to the [[Avian Liver - Anatomy & Physiology|liver]]

**Lies alongside, to the right, of the [[Proventriculus - Anatomy & Physiology|proventriculus]] and is found caudodorsally to the [[Avian Liver - Anatomy & Physiology|liver]]

Innervation is purely sympathetic<ref>{{citation|initiallast = Nance|initialfirst = D.M|finallast = Sanders|finalfirst = V.M|year = 2007|jtitle = Autonomic innervation and regulation of the immune system (1987-2007)|jor = Brain, Behavior, and Immunity|vol = 21(6)|range = 736-745}}</ref> and nerve fibres travel with the artery into the spleen.

Innervation is purely sympathetic<ref>{{citation|initiallast = Nance|initialfirst = D.M|finallast = Sanders|finalfirst = V.M|year = 2007|jtitle = Autonomic innervation and regulation of the immune system (1987-2007)|jor = Brain, Behavior, and Immunity|vol = 21(6)|range = 736-745}}</ref> and nerve fibres travel with the artery into the spleen.

===Histology===

===Histology===

<gallery perrow="3">

<center><gallery>

Image:LH_Spleen_Rat_Histology.jpg|<p>'''Gross view (rat)'''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Histology.jpg|<p>'''Low magnification view (rat)'''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_Histology.jpg|<p>'''Red & white Pulp (rat) '''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_Histology.jpg|<p>'''Red & white Pulp (rat) '''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_2_Histology.jpg|<p>'''Central artery & PALS (rat) '''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_2_Histology.jpg|<p>'''Central artery & PALS (rat) '''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_3_Histology.jpg|<p>'''Trabecula and capsule (rat) '''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_3_Histology.jpg|<p>'''Trabecula and capsule (rat) '''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_4_Histology.jpg|<p>'''Trabeculae & erythrocytes (rat)'''</p>^{©RVC 2008}

Image:LH_Spleen_Rat_Higher_4_Histology.jpg|<p>'''Trabeculae & erythrocytes (rat)'''</p>^{©RVC 2008}

Image:LH_Spleen_Mouse_Higher_Histology.jpg|<p>'''Megakaryocyte & macrophages (mouse)'''</p>^{©RVC 2008}</gallery>

Image:LH_Spleen_Mouse_Higher_Histology.jpg|<p>'''Megakaryocyte & macrophages (mouse)'''</p>^{©RVC 2008}</gallery></center>

==Functions==

==Functions==

<p>Blood flows through the marginal sinus. This means that most antigens present in the blood come into contact with the [[Lymphocytes#B cells|B lymphocytes]] 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 [[Lymphocytes#B cells|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. This means that most antigens present in the blood come into contact with the [[Lymphocytes#B cells|B lymphocytes]] 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 [[Lymphocytes#B cells|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|protozoa]].</p>

<p>Following splenectomy this doesn’t occur and animals are predisposed to septicaemia and infection with blood [[Protozoa|protozoa]].</p>

==In pathology==

==In pathology==

*''[[Corynebacterium ovis]]'', [[Erysipelothrix rhusiopathiae#Swine erysipelas|swine erysipelas]], [[Francisella tularensis#Pathogenesis and pathogenicity|francisella tularensis]], [[Salmonella#Spleen|salmonella]], [[Salmonellosis|enteric salmonellosis]], [[:Category:Brucella species#Pathogenesis and pathogenicity|brucella]] & [[Yersinia#Clinical infections|yersinia]]

*''[[Corynebacterium ovis]]'', [[Erysipelothrix rhusiopathiae#Swine erysipelas|swine erysipelas]], [[Francisella tularensis#Pathogenesis and pathogenicity|francisella tularensis]], [[Salmonella#Spleen|salmonella]], [[Salmonellosis|enteric salmonellosis]], [[:Category:Brucella species#Pathogenesis and pathogenicity|brucella]] & [[Yersinia#Clinical infections|yersinia]]

*[[Poxviruses#Histopathology|Leporipoxviruses]] & [[Bovine Viral Diarrhoea Virus|bovine viral diarrhoea disease]]

*[[Poxviruses#Histopathology|Leporipoxviruses]] & [[Bovine Viral Diarrhoea Virus|bovine viral diarrhoea disease]]

*[[Pigmentation and Calcification - Pathology#Haemosiderin|Haemolytic disorders]]

*[[Pigmentation - Pathology#Haemosiderin|Haemolytic disorders]]

==References==

==References==

<references/>

<references/>

[[Category:Spleen]]

[[Category:Spleen]]