Downing Hematopoiesis and Bone Marrow Flashcards
Hematopoeitic tissue is derived from:
Mesenchyme
**except Thymus (endoderm)
5 sites of prenatal hematopoiesis:
yolk sac
liver
spleen
bone
thymus
First hematopoiesis occurs in the yolk sac and forms undifferentiated pluripotent stem cells known as:
colony forming units (CFUs)
When does lymphopoiesis in the spleen cease:
never, lifelong process
**erythropoiesis and granulopoiesis end in 7th-8th fetal month
First bone to develop a medullary cavity for myeloid tissue?
clavicle
Where do T-cells get educated?
thymus
Bone marrow type that hosts hematopoiesis?
Red Marrow of skull, ribs, sternum, vertebral bodies, cancellous bone, long and short bones, iliac crest
**yellow marrow just fat and blood vessels
Cells in myeloid stroma:
fibroblasts
macrophages
fat cells
osteogenic cells
endothelial cells
Fibers in myeloid stroma:
collagenous
reticular
Contents and function of myeloid tissue sinusoids:
sinusoidal capillaries
- connect arterial to venous circ.
- permit red and white cells to enter circ.
Erythropoietin:
where is it from?
what induces it?
what does it do?
kidney and other areas
induced by hypoxia
increases number of hgb forming cells by stimulating stem cells (CFU-E)
Describe the erythrocyte lineage from beginning to mature RBC:
Blast cell (proerythroblast)–>basophilic erythroblast–>polychromatophilic erythroblast (last mitotically active cell) –> orthochromatophilic erythroblast –> reticulocyte –> RBC
In granulopoiesis, specific granules gradually _______ in # and azurophilic granules gradually _______ in number as cells mature.
increase
decrease
Name the three granulocytes?
Basophills
Eosinophils
Neutrophils
Describe granulopoiesis from beginning to end:
Myeloblast (Blast cell)–> promyelocyte –> myelocyte (last mitotically active stage) –> metamyelocyte –> band cell –> mature leukocyte
