unit 6 Flashcards
hematopoiesis
the process of producing blood cells, including formation, development and differentiation
plasma
liquid matrix consisting of proteins and other regulatory molecules
erythrocytes
red blood cells, hemoglobin and no nucleus
thrombocytes
formed elements involved in coagulation
leukocytes
white blood cells, involved in host defense including innate and adaptive immunity
what are granulocytes
leukocytes with specific cytoplasmic granules
mononuclear cells
agranular lymphocytes and monocytes involved in immune effector, helper and accessory functions
steps in hematopoiesis
stem cells -> progenitor cells -> precursor cells -> differentiated, functional cells types
hematopoietic stem cells
self-renew and regenerate every cell type in the hematopoietic system
capable of reconstituting the entire bone marrow
what cell markers can be used to identify hematopoietic stem cells?
CD34, CD90
hematopoietic progenitor cells
more restricted in differential potential than HSC
how are progenitors with different potential to form specific mature cells types defined?
function, cell surface markers, response to specific growth factors/cytokines
what are the five sites of blood production?
yolk sac
aorta-gonad-mesonephros
fetal liver
spleen
bone marrow
where does the first phase of hematopoiesis begin?
in the yolk sac in third week of gestation
characterized by formation of blood island in wall of yolk sac
what compartments does bone marrow include?
vascular and hematopoietic
what is the GATA2 transcription factor for?
HSC formation and function
what is the GATA1 transcription factor for?
erythropoiesis
what is the Pu.1 transcription factor for?
to commit cells to myeloid lineages
what are some extrinsic regulatory factors?
aka growth factors
produced in stromal cells to stimulate HSC survival
what is aplastic anemia?
there is not enough cell production for hematopoiesis
hypocellularity
what is myeloid leukemia?
packed, hypercellular marrow
what is the hematopoietic niche?
a specialized microenvironment consisting of stromal cells that produce supportive cytokines such as SCF and local microvasculature
what does the hematopoietic niche support?
hematopoietic stem and progenitor cells
what keeps cells in the undifferentiated state?
high levels of stem cell factor
what is colony formation used for?
evaluation of stem/progenitor cell potential and frequencies in bone marrow and peripheral blood
what does the updated model of hematopoiesis suggest?
there is a continuum of differentiated states rather than discreet populations of progenitors with fixed linage potential
what are the functions of blood?
transport O, CO2, nutrients, hormones, heat, waste
regulate fluid homeostasis, pH, body temp, water content
protects against infections and excessive loss by clotting
what are some of the proteins in plasma
albumin, globulins, fibronogen
what does albumin do?
maintains proper concentration gradients between blood and extracellular tissue fluid
what do globulins do?
secreted by plasma cells and are involved in the humoral response
what does fibrinogen do?
participates in coagulation
is produced in the liver
what is serum
plasma minus fibrinogen and some clotting factors
lacks coagulation factors
what stain is used for blood smear preparation?
Wright Giemsa
normal blood cell percentages
red blood cell development
common myeloid progenitor to megakaryocytic-erythrocyte progenitor to pro erythroblast
then basophilic, polychromatic, orthochromatic, reticulocyte
what are changes observed as RBCs develop?
cytoplasm staining goes from blue to pink
cells get smaller
cell nuclei get smaller
heterochromatin condenses
RNA content decreases
what is the major function of RBCs?
transport oxygen from pulmonary capillaries to tissues
what allows for the deformability of RBCs?
ankyrin, spectrin, band 3, band 4.1
what are some of the extrinsic regulators of RBC production?
hormones (erythropoietin), interleukin-3 and interleukin-4, necessary nutrients
what are intrinsic regulators of RBC production?
transcription factor GATA1
what is the structure of hemoglobin?
2 alpha globin and 2 beta globin chains with 4 heme groups
thrombopoiesis (platelet formation)
bipotent progenitor cell
megakaryocyte-committed progenitor
megakaryoblasts
what does thrombopoietin cause?
stimulation for DNA to replicate without cell division in megakaryocytes, increasing from 8n to 64n (endomitosis)
what is the platelet producing machine
megakaryocyte
what is the main function of the platelet?
hemostasis/coagulation
what do granulocytes originate from?
multipotent progenitors, common myeloid progenitor, granulocyte-monocyte progenitor
what are the 6 morphologically identifiable stages involved in neutrophil maturation
myeloblast
pro-myelocyte
myelocyte
metamyelocyte
band cell
mature neutrophil
mitotic phase of granulopoiesis
lasts 1 week and proliferation stops after reaching myelocyte stage
post-mitotic phase of granulopoiesis
involves specific granule formation in bone marrow, lasts about 1 week
what are basophils formed from?
from a common basophil-mast cell progenitor (tissue resident granulocyte)
what triggers development toward basophil?
CCAAT/enhancer-binding protein alpha (CEBPalpha)
what triggers development toward eosinophils?
IL-3 and IL-5
what is granulocyte function in phagocytosis?
neutralizing invading bacteria
how are monocytes produced?
in bone marrow from multipotent common myeloid progenitors
what are the distinct stages of monocyte differentiation
promonoblast
monoblast
promonocyte
monocyte
what controls extrinsic regulation of monopoiesis?
IL-3
what regulates monopoiesis intrinsically?
Pu.1 and Egr1 transcription factors
what does the final stage of maturation for monocytes require?
GM-CSF and M-CSF
differentiate into tissue macrophages
what transcription factor is needed for T lymphocytes?
GATA3
what is intrinsic factor leads to B lymphocytes?
Pax5
what is NK cell differentiation dependent on?
IL-2 and IL-15
