Changes

* Formation of B cells and T cells ([[Leukopoiesis#Lymphopoiesis|Lymphopoiesis]])

* Formation of B cells and T cells ([[Leukopoiesis#Lymphopoiesis|Lymphopoiesis]])

 

===Fetal===

==Foetal Haematopoeisis==

====Yolk Sac Phase====

====Yolk Sac Phase====

<p>Blood islands from the mesoderm  form in the yolk sac early in gestation. They provide primitive erythrocytes to support the developing embryo. These blood islands also give rise to the haematopoietic stem cells.</p>

<p>Blood islands from the mesoderm  form in the yolk sac early in gestation. They provide primitive erythrocytes to support the developing embryo. These blood islands also give rise to the haematopoietic stem cells.</p>

====Hepatic Phase====

====Hepatic Phase====

Occurs within [[Foetal Liver]]

Haematopoeisis occurs within the [[Foetal Liver]]

====Bone marrow phase====

====Bone marrow phase====