Lecture 13 - Hematopoiesis Flashcards
What are the characteristics of stem cells? (4)
- proliferate extremely well
- self-renewing
- differentiate into several different cell types
- may reconstitute after tissue injury
What are the different types of stem cells and what differentiates them?
Totipotent:
- can give rise to all cell types, embryonic and extraembryonic
- present only in zygotes
Pluripotent:
- can give rise to all embryonic cells and adult tissues
- embryonic stem cells
Multipotent:
- can give rise to all cells only of a certain lineage
- adult stem cells
What are the different classifications of leukocytes?
Granulocytes:
- neutrophils
- basophils
- eosinophils
Agranulocytes:
- monocytes
- lymphocytes
Describe hematopoietic sites found at 2-8 weeks of gestation?
- islands of hematopoiesis (blood islands) in yolk sac wall
- nucleated erythrocytes
- no leukocytes formed
Describe hematopoietic sites found at 8-28 weeks of gestation?
- hematopoiesis occurs first in the liver and later in the spleen
- hematopoiesis at these sites stop around time of birth
Describe hematopoietic sites found at 6 months of gestation and after birth?
-hematopoiesis occurs in the red bone marrow
Where is bone marrow found and what type is found in these locations at different ages?
Red bone marrow: -prior to puberty —skull —ribs —sternum —vertebrae —clavicles —pelvis —long bones -after puberty —as above except long bones
Yellow bone marrow
-replaces red bone marrow with age with the exception of the iliac crest and sternum
List and describe the histological features of bone marrow. (4)
Stroma:
- contains fibroblasts, reticular cells, adipose cells, and endothelial cells
- synthesizes and secretes hematopoietic growth factors
Parenchyma:
-consists of various lineages of hematopoietic cells
Sinusoids:
- endothelial-lined spaces connecting arterial and venous vessels
- allow mature blood cells to enter circulation
Hematopoietic cords:
-bands of parenchyma and stroma between sinusoids
What are the different types of hematopoietic cells and what is the prevalence of each?
Granulocytopoiesis
-60%
Erythrocytopoiesis
-30%
Thromboplastin-, mono-, and lymphocytopoiesis:
-10%
What do myeloid stem cells give rise to?
- erythroid CFU
- megakaryocyte CFU
- basophil CFU
- eosinophil CFU
- granulocyte-macrophage CFU
What do lymphoid stem cells give rise to?
- T-cell progenitor (matures in thymus)
- B-cell progenitor (matures in bone marrow)
Describe the differentiation pathway that results in the production of a macrophage.
What cells are capable of dividing (*) and which are found in the blood (**)?
- myeloid stem cell
- granulocyte-macrophage CFU
- monocyte colony stimulating factor (M-CSF) causes differentiation into monoblast (*)
- promonocyte
- monocyte (**)
- macrophage
Describe the differentiation pathway that results in the production of a neutrophil.
What cells are capable of dividing (*) and which are found in the blood (**)?
- myeloid stem cell
- granulocyte-macrophage CFU
- granulocyte colony-stimulating factor (G-CSF) causes differentiation into myeloblast (*)
- promyleocyte (*)
- myelocyte (*)
- metamyelocyte
- band cell (**)
- neutrophil (**)
Describe the differentiation pathway that results in the production of a eosinophil or basophil.
What cells are capable of dividing (*) and which are found in the blood (**)?
- myeloid stem cell
- myeloblast (*)
- promyelocyte (*)
- myelocyte (*)
- metamyelocyte
- band cell (**)
- eosinophil or basophil (**)
Describe the differentiation pathway that results in the production of a platelet.
What cells are capable of dividing (*) and which are found in the blood (**)?
- megakaryocyte CFU
- thrombopoietin causes differentiation into megakaryoblast
- megakaryocyte
- platelets (**)
