CPR 02 - Hematopoiesis Flashcards
Discuss where and when hematopoiesis occurs before birth.
Where does hematopoiesis primarily occur after birth?
It only occurs in bone marrow after birth and most of it occurs in the vertebrae, pelvis, sternum, and ribs.
Draw out the graph of the cellularity of hematopoiesis before and after birth.
Where are most adult blood cells found and what special types of tissues (meaning they do not normally produce these tissues) can each stem cell population produce?
Discuss the different stem cell potentcy classes.
Draw out the hematopoiesis flow chart.
Differentiate pluripotent stem cells, progenitor cells, and precursor cells.
Pluripotent Stem Cells - capable of producing all blood cell lineages and self renewal
Progenitor Cell - a cell that has the tendency to differentiate into another type of cell. Similar to a stem cell but with less specificity. When a progenitor cell divides it forms two precursor cells
Precursor Cell - a morphologically distinct, partially differentiated cell that is destined to become a specific cell type (unipotent). Also known as blast cells
What is a stem cell niche and its primary functions?
A stem cell niche is defined as a spatial structure (microenvironment) in which stem cells are housed and maintained by allowing self-renewal in the absence of differentiation. A stem cell niche will actually inhibit differentiation.
What creates the stem cell niche for HSCs (hematopoietic stem cells)? What is this structure composed of?
Bone marrow stroma composed of mesenchymal stem cells that resides in cancellous bone in the epiphysis of long bones.
What is a vascular niche? Discuss its purpose and composition.
What are the arrows pointing to?
Discuss the general structure of bone marrow and the two types of bone marrow.
What is this?
Bone marrow
What do hematopoietic growth factors do?
They bind to progenitor cell receptors and trigger their differentiation into different cell types
List the 3 major heamtopoietic growth factors, what tissue produces them, and what they do.
What will occur is a hematopoietic cell does not receive a growth signal?
It will die
What is myelopoiesis?
the production of bone marrow and of all cells that arise from it, namely, all blood cells.
What are the various types of myelopoiesis?
What is lymphopoiesis?
Formation of lymphocytes
Where does erythropoiesis occur and what is the main stimulus for it?
It occurs in adult red bone marrow of certain bones and is stimulated primarily by hypoxia (causing the kidneys to release erythropoietin).
List all the cellular stages of erythropoiesis. Describe the distinguishing characteristics of each cellular stage.
- Pluripotent Stem Cell
- Myeloid Stem Cell
- Colony-forming unit-erythrocyte
- Proerythroblast - no hemoglobin, large nucleus, basophilic cytoplasm
- Basophilic (early) Erythroblast - some hemoglobin, condensing nucleus
- Polychromatophilic Erythroblast - muddy cytoplasm
- Orthochromatophilic (late) Erythroblast (normoblast) - increased hemoglobin
- Reticulocyte - no nucleus, some ribosomes (blue with cresyl blue stain)
- Erythrocyte - only hemoglobin, no ribosomes
What controls granulocytopoiesis and how long does it typically take?
Granulocyte formation is controlled by cytokines; takes about 11 days
List the cellular stages involved in granulocytopoiesis. Describe each stages defining characteristics.
- Pluripotent Stem Cell
- Myeloid Stem Cell
- Colony-forming unit-granulocyte macrophage (for neutrophils only)
- Myeloblast (common precursor) - no granules, cytoplasmic blebs
- Promyelocyte - large nucleus, azurophilic granules
- Myelocyte - condensed round nucleus, specific granules
- Metamyelocyte - kidney shaped nucleus, specific granules
- Band (stab) - C shaped nucleus, specific granules
- Mature form of neutrophil, eosinophil, or basophil
List the cellular stages involved in monocytopoiesis. Descibe each stages defining characteristics.
- Pluripotent stem cell
- Myeloid stem cell
- Colony-forming unit-granulocyte macrophage
- Monoblast - large, undifferentiated cells
- Promonocytes - kidney shaped nucleus, azurophilic granules
- Monocytes - “sky” blue cytoplasm, kidney shaped nucleus
- Enter the circulation, proceed to tissue spaces, differentiate into macrophages
List the cellular stages involved in throbopoiesis. Describe the defining characteristics of each stage.
- Puripotent stem cell
- Myeloid stem cell
- Colony-forming unit-megakaryocyte
- Megakaryoblast - endomitosis (replication of chromosomes without cell division)
- Megakaryocyte - large multi-lobed nucleus
- Platelets are formed from fragments of megakaryocyte cytoplasm (1000s per cell)
- Platelet demarcation channels
List the cellular stages to lymphopoiesis. Describe the defining characteristics of each stage.
- Pluripotent stem cell
- Lymphoid stem cell
- Colony forming units-lymphocyte (B=bursa equivalent; T=thymus)
- Lymphoblasts - large, undifferentiated
- Prolymphocytes - medium sized, condensing chromatin, no cell surface antigens
- Some migrate from bone marrow to thymus and become T-cells, others remain in bone marrow, become B-cells, and migrate to lymph tissues
From what part of the body is a bone marrow aspiration usually taken?
Iliac Crest
