Benign heme basics

Question 1

where does early hematopoiesis take place?

Answer 1

3-5 weeks –> yolk sac
4-6 weeks–> aorta-gonad-mesonephrosis
2-6 months–> liver and spleen
4 months–> bone marrow

Question 2

what are the embryonic Hb types?

Answer 2

gower and portland

Question 3

hematopoietic and endothelial cells share a common precursor called

Answer 3

hemangioblast

Question 4

Hb affinity curve

Answer 4

right shift = decreased affinity, unloads more easily

left shit = greater affinity, less unloading

HbF shifts curve to the left

Question 5

what is the difference between HSC and HPC (progenitor)

Answer 5

HSC= pluripotent undifferentiated cells that can replenish; unlimited cell divisions

HPC = oligopotent- can replenish specific lineage cells bc it already started to differentiate and commit towards a specific lineage; limited cell divisions

but they are morphologically indistinguishable which is why its often called HSPC

Question 6

what is HSC homing?

Answer 6

various receptors and chemokines play an important role in homing which is when HSC migrates to the bone marrow; stromal derived factor 1 (SDF1) and its receptor CXCR4 are expressed on HSC.

Question 7

name some important transcription factors in hematopoiesis

Answer 7

HOX, GATA, RUNX1, MLL, CEBPa, PAX5, Ikaros and PU.1

Question 8

formula for cellularity in the bone marrow

Answer 8

100-age = cellularity