Hematopoiesis Flashcards
Self-renewing
able to create another undifferentiated stem cell (stem cells have self-renewing ability, but not blast cells)
Differentiation
cells shrink, lose nucleoli, granules appear, nucleus changes shape
Which cells differentiate and self-renew
colony forming unites (progenitor cells that differentiate into a limited number of cell types) can replicate and produce blast cells
Draw schematic of changes in properties of a hemopoietic cell during differentiation (potentiality, mitotic activity, self-renewing capacity, influence of growth factors, differentiated functional activity, morph characteristics)
PIC
erythropoietin
Growth factor; produced by renal cells, stim RBC development
GM-CSF
growth factorl produced by lymphocytes, endothelium & fibroblasts; stim granulocyte and macrophage development
G-CSF
growth factor; produced by macrophages, endothelium and fibroblasts; stim granulocyte development
IL-3
growth factor; produced by T-lymphocytes; stim production of all myeloid cells
Thrombopoeitin
growth factor; produced by liver and kidney; stim production of platelets.
where does blood cell development occur in the early fetus?
yolk sac
where does blood cell development occur in the mid-fetal months?
liver and spleen
where does blood cell development occur in the late fetal months?
bone marrow
where does blood cell development occur in an adult?
bone marrow/medullary (mostly in vertebrae, ribs, pelvis, sternum), but liver and spleen can resume production if necessary (extramedullary)
Red marrow characteristics
active marrow, relatively less fat and more cells making blood cells
yellow marrow characteristics
inactive marrow, lots of fat; has the ability to convert back to red marrow if necessary
two types of marrow
red and yellow
changes in marrow with age
larger percentage of adipose vs. blood cells as you age
bone marrow compartments (2)
vascular and extravascular
vascular bone marrow compartment
contains venous sinuses through marrow
extravascular/stroma bone marrow compartment
contains hematopoetic cells, reticular fibers, adventitial cells/stromal (inc. fibroblasts), fat cells
what provides blood supply for the bone marrow?
periosteal and nutrient arteries
Normal blood count of bone marrow
fewer blasts than more mature cells; 3:1 myeloid to erythroid ratio
erythroblastic islands
contain developing immature red blood cells
stages of erythrocyte development (6)
- proerythroblast 2. basophilic erythroblast 3. polychromatophilic erythroblast 4. orthochromatophilic erythroblast 5. reticulocyte 6. mature erythrocyte
Morphological changes in erythrocyte development
cells gets smaller
nucleus condenses and is extruded
cytoplasmic eosinophilia increases
Why does cytoplasmic eosinophilia increase as the erythrocyte matures?
increased Hb production and loss of rER
How do red blood cells get into the blood stream?
fuse their plasma membrane with endothelial cell PM to create a transient pore –> squeeze through endothelium to get into bloodstream
Granulocyte development location
further from sinuses than megakaryocytes and erythroblastic islands
Granulocyte development stages
1st week = mitotic (myeloblast -> promyelocyte -> myelocyte)
2nd week = post-mitotic (metamyelocyte -> band cell -> mature PMN)
how long do white cells live in tissue?
1-2 days
how long do red cells live in the body?
120 days
why is the nucleus of the megakaryocyte lobed?
endomytosis
