Changes

*[[Secondary Lymphoid Tissue - Anatomy & Physiology|Secondary lymphoid organ]]</p>

*[[Secondary Lymphoid Tissue - Anatomy & Physiology|Secondary lymphoid organ]]</p>

===Erythrocytes & Platelets===

===Erythrocytes & Platelets===

<p>In the foetus the spleen also has a role in [[Haematopoiesis - Anatomy & Physiology|haematopoiesis]] when it becomes the main [[Erythrocyte - Anatomy & Physiology|erythrocyte]] producing organ during the hematopoietic transitional phase.</p>

<p>In the foetus the spleen also has a role in [[Overview of Haematopoiesis - WikiBlood|haematopoiesis]] when it becomes the main [[Erythrocyte - Anatomy & Physiology|erythrocyte]] producing organ during the hematopoietic transitional phase.</p>

<p>In the developed animal the red pulp is involved in the removal of aged, damaged or abnormal erythrocytes (along with the liver and bone marrow). As [[Erythrocyte - Anatomy & Physiology|erythrocytes]] age they become less supple and this causes them to become damaged when they pass through the very narrow capillaries of the spleen, after which they are phagocytised by splenic [[Macrophages - Anatomy & Physiology|macrophages]]. If a splenectomy is performed the number of aged [[Erythrocyte - Anatomy & Physiology|erythrocytes]] in circulation increases.</p>

<p>In the developed animal the red pulp is involved in the removal of aged, damaged or abnormal erythrocytes (along with the liver and bone marrow). As [[Erythrocyte - Anatomy & Physiology|erythrocytes]] age they become less supple and this causes them to become damaged when they pass through the very narrow capillaries of the spleen, after which they are phagocytised by splenic [[Macrophages - Anatomy & Physiology|macrophages]]. If a splenectomy is performed the number of aged [[Erythrocyte - Anatomy & Physiology|erythrocytes]] in circulation increases.</p>

<p> The red pulp also acts as a storage site for [[Erythrocyte - Anatomy & Physiology|erythrocytes]]. The degree of storage is variable between species but is particularly notable in horses which during exercise under sympathetic activity can contract their spleen to increase the concentration of circulating [[Erythrocyte - Anatomy & Physiology|erythrocytes]]. In some species such as cats and rodents the red pulp acts as a storage site for [[Thrombocytes - Anatomy & Physiology|platelets]] and contains [[Thrombopoiesis - Anatomy & Physiology#Megakaryocyte|megakaryocytes]].</p>

<p> The red pulp also acts as a storage site for [[Erythrocyte - Anatomy & Physiology|erythrocytes]]. The degree of storage is variable between species but is particularly notable in horses which during exercise under sympathetic activity can contract their spleen to increase the concentration of circulating [[Erythrocyte - Anatomy & Physiology|erythrocytes]]. In some species such as cats and rodents the red pulp acts as a storage site for [[Thrombocytes - Anatomy & Physiology|platelets]] and contains [[Thrombopoiesis - Anatomy & Physiology#Megakaryocyte|megakaryocytes]].</p>