Hematopoiesis

Question 1

what do HSCs express on their surface

Answer 1

CD34

not unique to HSCs- also present in early differentiation and on leukemia cells

Question 2

what phase are most HSCs in? why?

Answer 2

G0 - to protect against toxic insults

Question 3

sites of hematopoeisis during development

Answer 3

yolk sack (primitive) -> liver –> liver + spleen –> bone marrow starts at 5 months

Question 4

where do definitive HSCs first arise?

Answer 4

wall of developing aorta before migrating to fetal liver

Question 5

signs of extra medullary hematopoiesis

Answer 5

frontal bossing (ex. beta thalessemia)
splenomegaly

Question 6

c-kit ligand/stem cell factor

Answer 6

stim stem cell –> pre B cells

Question 7

IL3

Answer 7

stim stem cells –> erythrocytes + lymphoid cells

Question 8

IL2

Answer 8

T cell growth factor

Question 9

erythropoietin

Answer 9

produced by kidney in response to low oxygen

leads to increased RBC production

Question 10

normal WBC to RBC ratio in the marrow

Answer 10

3 or 4:1

Question 11

RBC and WBC life span

Answer 11

RBC: 120 days
WBC: 6-7 hrs

Question 12

GM-CSF

Answer 12

stim production of myeloid cells from precursors, particularly monocytes and PMN (granulocytes) - GM

Question 13

G-CSF

Answer 13

stim production of granulocytes (PMNs) from precursors