Flashcards in Hematopoiesis (Part I) Deck (84)
What does hematopoiesis begin with?
the pluripotent stem cell
What is the first split off of the pluripotent stem cell?
it will become either a myeloid stem cell or a lymphoid stem cell
What stems from the myeloid stem cell?
erythroblasts, megakaryoblasts, monoblasts, and myeloblasts
what is derived from erythroblasts?
what is derived from megakaryoblasts?
what is derived from monoblasts?
What is derived from myeloblasts?
neutrophils, eosinophils, and basophils
What stems from the lymphoid stem cell?
a pre-B cell and a Prothymocyte
what is derived from the prothymocyte?
a T lymphocyte
What are the different sites of hematopoiesis in chronological order?
yolk sac, liver, spleen, and then finally the bone marrow
What happens to hematopoiesis shortly after puberty?
prior to puberty, hematopoiesis occurs throughout all bones in the body; however, shortly after puberty, hematopoiesis occurs in more of an axillary location including the skull, sternum, ribs, vertebrae, pelvis, and proximal femur
Within the bone marrow, there are two principal compartments. What are they?
the hematopoietic cell compartment and the marrow stromal compartment
What does the hematopoietic cell compartment of the bone marrow consist of?
an erythroblastic area, a myeloid area, megakaryocytes
What does the marrow stromal compartment consist of?
endothelial cells, adipocytes, stromal cells and fibroblasts, and macrophages
what is the purpose of the endothelial cells in the marrow stromal compartment?
they are fenestrated, so they allow the mature cells to come out into the circulation and become our peripheral blood
what is the main role of all of the stromal compartment cells?
they are responsible for helping us produce the hematopoietic growth factors
how can you calculate the percentage of cellularity a person should have in their bone marrow? and what does this tell us?
you subtract their age from 100; this helps us calculate to see if someone's bone marrow is hypocellular or hypercellular
How is the process of hematopoiesis regulated?
hematopoietic growth factors
where are hematopoietic growth factors produced?
in bone marrow by endothelial cells, stromal cells, fibroblasts, developing lymphocytes, and macrophages
what are the chief hematopoietic growth factors?
colony-stimulating factors (CSF), cytokines (interleukins), erythropoietin (EPO), Thrombopoietin (TPO)
what is the first potentiator of hematopoietic differentiation?
stem cell factor (SCF)
what is stem cell factor produced by?
fetal tissues and bone marrow
what is the main role of stem cell factor (SCF)?
it makes stem cells responsive to other cytokines
What interleukins act as hematopoietic growth factors?
IL-3, IL-6, IL-2
what is the role of IL-3 as a hematopoietic growth factor?
it influences the replication and growth potential of hematopoietic progenitors (non-lymphoid stimulator)
what is the role of IL-6 as a hematopoietic growth factor?
it stimulates megakaryocytes and neutrophil production; it is a key factor in leukemoid reaction; it acts as a B-cell growth factor
what is the role of IL-2 as a hematopoietic growth factor?
it acts as a B and T cell growth factor
What is G-CSF?
granulocyte colony-stimulating factor
what is G-CSF produced by?
endothelial cells, fibroblasts, and macrophages