Hematopoiesis Flashcards
Where does hematopoiesis occur in an embryo? What time frames?
Yolk sac: 0-2 months
Liver: 2-7 months
Bone Marrow: 7 months to birth
Where does hematopoiesis primarily occur after puberty?
“Axillary” location, Vertebrae and pelvis, sternum, ribs
Describe the hematopoietic cell compartment
highly vascular, contains hematopoietic stem cells, committed precursor cells, and maturing cells
Describe the marrow stromal compartment
contains a barrier of endothelial cells, adipocytes for energy, structural support by stromal cells and fibroblasts and macrophages
What are the main hematopoietic growth factors?
CSF, interleukins, EPO, TPO
Where are hematopoietic growth factors produced?
endothelial cells, stromal cells, fibroblasts, developing lymphocytes, macrophages
What is the function of SCF?
weak stimulator of hematopoiesis that makes stem cells responsive to other cytokines; produced by fetal tissues and bone marrow
What is the function of IL-3?
influences the replication and growth potential of hematopoietic progenitors
What is the function of IL-6?
Stimulates megakaryocytes and neutrophil production, key factor in leukemoid reactions
What is the function of IL-2?
Serves as a T-cell growth factor
What is the function of IL-2 combined with IL-6?
B-cell growth factor
What is the function of GM-CSF?
Stimulates the formation of all leukocytes and reticulocytes
What is the function of G-CSF?
Stimulates an increase in neutrophils
What is the function M-CSF?
Stimulates monocyte and macrophage production
What is the function of EPO?
Stimulates RBC production
What is the function of TPO?
stimulates an increase in megakaryocytes and platelets
What is a reticulocyte?
large, immature, nucleated RBC, with a residual reticular network of ribosomal material
What are some examples of differentiated macrophages throughout the body?
microglia, kupffer cells, alveolar macrophages, osteoclasts
What does plasma consist of?
dissolved proteins, glucose, ions, hormones, clotting factors
What does hematocrit measure?
volume percentage of red blood cells in blood
What is red cell distribution width (RDW)?
Measure of range in variation of RBC volume
What is MCV?
average volume of red blood cell
What is MCH?
average mass of hemoglobin in erythrocytes
What is MCHC?
concentration of hemoglobin in a given volume
What is RPI?
Corrected reticulocyte % based on RBC volume, reticulocyte production index
What is anisocytosis?
variation in RBC size, increase in RDW
What is poikilocytosis?
variation in RBC shape
Definition by anemia
decreased RBC volume