Erythropoeisis Flashcards
What stimulates the production of RBCs?
Compromised tissue oxygenation
Explain the process of erythropoesis
Haematopoetic stem cell–>CFU-GEMM–>BFU-E–>CFU-E—>Pronormoblast(proE–>basoE–>polyE–>orthoE)–>smaller normoblasts—>nucleus extrudes—>reticulocytes—>stay in BM for 24-48 hours—>circ in PB for 24-48 hours—>mature to RBC (reticulin removed in spleen)
As pronormoblasts progress to smaller normoblasts, what change to we see in the cells.
increase in Hb, decrease in mRNA, decrease in size, chromatin condenses.
Which RBC precursor is the first identified under microscopy?
The pronormoblast
The BFU-E matures and differentiates under the control of which regulatory factors?
IL-3, IL-9 and GM-CSF
Where are the specific sites of EPO release?
90% by the peritubular cells of the kidney
10% by the liver
What is EPO?
It is a heavily glycosylated polypeptide
What is its function?
It is the primary humoral regulator of erythropoesis and promotes the proliferation and survival of RBCS.
When does EPOs production increase?
Anaemia, decrease atmospheric oxygen, defective CVS and pulmonary function and decreased renal circulation.
How does it carry out its action?
It binds to EPO-R with dimerization and signal transduction including upregulation of transcription factors GATA and FOG-1 with increased erythroid specific gene expression and anti-apoptotic Bcl-XI (result= erythroblast survival)
What are the 2 broad cell types seen in the bone marrow?
Stromal cells and immunoregulatory cells.
Which cytokines inhibit erythroid colony formation?
TGF-B, INF-gamma, TNF
