hemopoiesis Definition ： Blood cells are short-lived, and they must be continually replaced by new cells formed in the generative process called hemopoiesis.    From Wordnik.com.  [Recently Uploaded Slideshows] Reference

Extramedullary hemopoiesis • When hematopoietic demand increases, liver, spleen and lymph nodes come back to the status to produce blood cells, hepatomegaly and splenomegaly appears, and maybe there are immature erythrocytes and granulocytes in circulating blood.    From Wordnik.com.  [Recently Uploaded Slideshows] Reference

2005, 2001 by Mosby, Inc. Hematopoiesis after birth Hematopoesis in bone marrow Extramedullary hemopoiesis 　　 Mosby items and derived items © 2005, 2001 by Mosby, Inc.    From Wordnik.com.  [Recently Uploaded Slideshows] Reference

Phase mesoblastic phase: The mesoblastic phase of hemopoiesis, occur in small islands of cells in the yolk sac and body stalk of the embryo. hepatic phase: At about 6 weeks of gestation, round basophilic precursors of erythrocytes can be found in the primordium of the liver, and the spleen initiating the hepatic phase of hemopoiesis. myeloid phase: After medullary cavities develop in the long bones, blood formation is initiated there, establishing the myeloid phase of hemopoiesis which continues throughout adult life.    From Wordnik.com.  [Recently Uploaded Slideshows] Reference