Changes

<p>The haematopoietic cells produce the vast majority of blood cells in the body (haematopoiesis). In young animals this occurs in most bones in the body but in mature adults this is limited to membranous bones in the body.</p>

<p>The haematopoietic cells produce the vast majority of blood cells in the body (haematopoiesis). In young animals this occurs in most bones in the body but in mature adults this is limited to membranous bones in the body.</p>

<p>To enter circulation newly formed cells press against the sinusoid wall, temporally fusing to it and creating an opening. The cell then passes directly into the circulation and the membrane repairs itself. Mature [[erythrocytes]] immediately enter circulation, however the marrow stores leukocytes and consequently contains around ten times more [[Leukocytes - Anatomy & Physiology|leukocytes]] than found in circulation</p>

<p>To enter circulation newly formed cells press against the sinusoid wall, temporally fusing to it and creating an opening. The cell then passes directly into the circulation and the membrane repairs itself. Mature [[erythrocytes]] immediately enter circulation, however the marrow stores leukocytes and consequently contains around ten times more [[Leukocytes - Anatomy & Physiology|leukocytes]] than found in circulation</p>

<p>[[Thrombopoiesis - Anatomy & Physiology#Megakaryocyte|Megakaryocytes]] residue alongside the sinusoid membrane but do not leave the tissue, rather they release their platelets and then withdraw from the membrane.</p>

<p>[[Thrombopoiesis - WikiBlood#Megakaryocyte|Megakaryocytes]] residue alongside the sinusoid membrane but do not leave the tissue, rather they release their platelets and then withdraw from the membrane.</p>

===Lymphoid tissue===

===Lymphoid tissue===

*In some primates it acts as a [[Primary Lymphoid Tissue - Anatomy & Physiology|primary lymphoid organ]]

*In some primates it acts as a [[Primary Lymphoid Tissue - Anatomy & Physiology|primary lymphoid organ]]