e Development of Hematopoietic Organs Hematopoiesis after birth Bone marrow hematopoiesis Extramedullary hematopoiesis In diseases status: red cell production hematopoietic tissue↑ blood production expands to replace fatty marrow ood ce lls production extends to extramedullary sites liver and spleen)Development of Hematopoietic Organs • Hematopoiesis after birth – Bone marrow hematopoiesis – Extramedullary hematopoiesis • In diseases status: red cell production hematopoietic tissue. • blood production expands to replace fatty marrow. • blood cells production extends to extramedullary sites ( liver and spleen)