Hematopoiesis Flashcards
Continues regulated process of blood production including the renewal, proliferation, differentiation and maturation
Hematopoiesis
Formation, development and specialization of all functional blood cells and its components
Hematopoiesis
Blood cells are released from the
bone marrow
Bones responsible in the formation of blood cells:
Long bones
Hematopoiesis starts during the time of conception
(union → proliferation → totipotent → pluripotent → multipotent → formation of cells)
Most hematopoiesis are erythroid (RBC)
Prenatal Hematopoiesis
19th day of gestation (2nd week of fetal life) formation of blood islands in yolk sac (mesodermal extraembryonic layer), aggregation of primitive cells
Mesoblastic Period
chief site of mesoblastic period
Yolk sac
future blood vessels
Angioblast
produces measurable amount of hemoglobin that happens intravascularly
9th week of fetal life, development of primitive erythroblast (PE)
Enumerate the Three embryonic forms of hemoglobin:
o Gower I
o Gower II
o Portland
4 to 5 gestational weeks (stars in the 2nd month) which happens extravascularly
Hepatic Period
chief site; 3rd month of fetal life
Liver
Recognizable clusters of developing erythroblast, granulocytes, and monocytes
Liver
Lymphoid cells already appear
Liver
First organ to fully develop in the fetus, major site of T cell production (cellular)
Thymus
B cells produced in (humoral cells)
Kidney and spleen
Spleen-active in:
- Erythropoiesis
- Myelopoiesis
- Lymphopoiesis
Spleen-active (until the end of normal gestation (splenic)
Erythropoiesis
Spleen-active (becomes minimal by the 5th month)
Myelopoiesis
Spleen-active (that is lifetime)
Lymphopoiesis
During the Hepatic Period these blood components are produced
NRBC’s, Granulocytes, Monocytes, Lymphocytes and Megakaryocytes
Enumerate the Hemoglobin/s produced during the Hepatic Period
o Hb A
o Hb A2
o Hb F
also developed during hepatic period
Lymph nodes
Starts on the 5th month of fetal life
Medullary/Myeloid Period
chief site; occurs in the medulla/inner part of the bone cavity
Red bone marrow
Development of cells increases at birth
Medullary/Myeloid Period
will migrate to the core of the bone (embryonic tissue) → differentiate into skeletal and hematopoietic blood cells
Hematopoietic Stem Cells (HSCs) and mesenchymal cells
Hematopoietic Stem Cells (HSCs) and mesenchymal cells will migrate to the core of the bone (embryonic tissue) → differentiate into
skeletal and hematopoietic blood cells
Myeloid to erythroid ratio in the 21st week of gestation
3:1
What months/ weeks does the bone marrow (shaft of long bones) will be the main site?
By the 6 month/24 weeks of gestation
By the 6 month/24 weeks of gestation
bone marrow (shaft of long bones) is the main site
begins to appear and gradually increases in concentration
HB A1
During Medullary/Myeloid Period these (hormone/ growth factor/hemoglobin) becomes measurable and determined
EPO, G-CSF, GM-CSF, Hb F, Hb A2
