10.09.18 Hematopoiesis Flashcards
Where does hematopoiesis occur from birth to 4 years?
Where does it occur in adulthood?
All marrow cavities
Axial skeleton and proximal long bones
What are the essential components of hematopoiesis?
Stem cells, Stromal (fat cells, macrophages, endothelial cells, and fibroblasts), Growth factors (cytokines, growth factors, interferons)
What are the non-lineage specific growth factors that act on pleuripotent and multipotential stem cells to initiate self-renewal and differentiation
- IL-3
2. GM-CSF
What are the lineage specific growth factors that act on committed progenitor cells, involved in differentiation and maturation of blood cells
- G-CSF
- M-CSF
- IL-5
- EPO
- TPO
proliferation to produce more stem cells
Self-renewal
production of highly specialized mature cell types, and from there produce more developmentally restricted cells (progenitor cells)
Differentiation
What cells undergo self-renewal and differentiation?
Pluripotent stem cell (PPSC)
this cell has the capability of differentiating into either lymphoid or myeloid (non-lymphoid) cells
Multipotential cell
this cell is committed to a cell lineage; progressive restriction in developmental potential ensures a tremendous amplification in cell numbers
Progenitor cells
These cells develop into mature cells of the various cell types and exhibit morphological characteristics specific to their lineage
Precursor cells
What is the order of hematopoietic stem cell differentiation?
Multipotential –> Progenitor cells –> Precursor cells
What is the order for erythropoiesis?
- Proerythroblast
- Basophilic erythroblast
- Polychromatophilic erythroblast
- Orthochromatophilic erythroblast
- Reticulocyte
- Mature RBC
What is the order for granulopoiesis?
- Myeloblast
- Promyelocyte
- Myelocyte
- Metamyelocyte
- Band cell
- Neutrophil
What cell matures into monocytes?
Monoblasts
What do monocytes do after they leave the blood stream ?
Mature to tissue macrophages
What cells mature into multiolobed giant cells by endomitotic divisions
Megakaryocytes
This type of cell is responsible for the production of platelets
Megakaryocytes
- Consists of ~50% fat cells;
- Has more myeloid cells than erythroid cells
- Megakaryocytes are 2-5 per high power field
- Plasma cells <3%
- Lymphocytes <20%
Normal Adult Bone Marrow
A needle is inserted into the marrow and a liquid sample is sucked into a syringe
Aspiration
provides a solid core of bone marrow and is examined as a histological specimen after fixation
Biopsy
How long do normal erythrocytes survive for after release from the bone marrow?
120 days
Lysosomal enzymes in the presence of H2O2, superoxide, and halides digest the ingested bacteria
Neutrophils
Present in the mucosa of GI, bronchial/lower GU tracts; defense against parasites and participate in allergic rxns
Eosinophils
Blue-black granules that contain histamine and are important in certain allergic rxns
Basophils
