Bone Marrow Flashcards
What is the mesoblastic phase? when?
Aggregates of blood cells form in the yolk sac called blood islands. stats 2 weeks post conception
What is the hepato-splenic phase? When?
When organs start to appear. 2 months
What is the myeolid phase? When is it
Starts at the end of the second trimester and continues throughout life, RBC formation starts in bone marrow
When do leukocytes appear during gestation
8 weeks
Where does hemopoiesis occur in children
Marrow of long bones like femur and tibis
Where does hemopoiesis occur in adults
Mainly in pelvis, cranium, vertebrae and sternum
Found in cancellous bone (spongy bone)
What is yellow marrow
located in long bones and is highly inflitrated with fat, not hemopoietic but can become so if necessary
What are sinusoids in bone marrow
large vessels with thin enothelial cells around them. surrounded by reticular fibers and cells
What is the stroma in bone marrow
3D network fo adventitial/reitcular cells and reticular fibers.
everything not involved in hemtopoesis
Parenchyma
bone marrow divided into hematopoeitc compartments responsible for synthesis or RBCs and WBCs
What are adventitial cells in bone marrow
basically fibroblasts. helps divide bone marrow cavity into smaller compartments
What does a megakaryocyte make
Platelets. Largest cells you can see if marrow
Are stem cells common in bone marrow? do they have mitotic activity
Rare in bone marrow, ow mitotic activity, potentiality.
Progenitor Cells
not morphologically distinguishable, have high mitotic activity, common in marrow and lymphoid organs, mono or bi potential
What type of cells during meatopoiesis does morphologic differentiation begin
Precursor cells (blasts)
Precursor Cells are called what? mitotic acticity? how many types of cells can they become
Blasts. They are where you can start to see morphological differentiation; high mitotic activity
common in marrow and lymph
monopotentital
do Mature Cells of hematopoisis have mitotic activity
No
Which hematopoietic cells are most influenced by growth factors:
stem cells, progenitor cells, blasts (precursor), mature cells
progenitor, precursor
Which hematopoietic cells are self renewing
stem cells, progenitor cells, blasts (precursor), mature cells
Mostly stem cells, a little bit progenitor
Which hematopoietic cells have mitotic activity
stem cells, progenitor cells, blasts (precursor), mature cells
all but mature cells
What is an erythroblast? How big is it? What is th enucleous, cytoplasm like
Large, loose lacey chromatin, visible nucleoli, basophilic cytoplasm
What is formed from a proerythroblast? What is a new important feature
what is the nucleus like?
Basophilic erythroblast. onset of Hb synthesis
strongly basophilic cytoplasm, condensened nucleus, no nucleoli
What is ater a basophilic erythroblast?
Polychromatophilic ertryhoblast. the cytoplasm is full of Hb, less polyribosomes, final stage with mitosis
What is the last stage with mitosis during erythrocyte formation
Polychromatophilic ertryhoblast.
