Hematopoiesis Flashcards
Define hematopoiesis
formation of blood
Components of Bone Marrow
Red marrow - hematopoietic progenitors and developing cells. decreases with age
Yellow marrow - inactive, fat cells, macrophages, mesenchymal cells. can convert to red marrow in times of need.
Mesoblastic stage
Age - embryo
Organs - yolk sac
Cells - nRBC
Hepatic stage
Age - embryotic-fetal (6 weeks - 3 months)
Organs - liver
Cells - RBC
Medullary (Myeloid stage)
Age - fetal (5+ months)
Organs - Bone marrow, Spleen, Lymphnodes
Cells - All cells
Stromal (support cells)
Endothelial - secrete cytokines
Adipocytes - secrete cytokines, growth factors
Macrophages - phagocytosis, secrete cytokines, regulate hematopoeisis
Lymphocytes - secrete cytokines
Osteoblasts - bone forming cells
Osteoclasts - bone resorbing cells
What secretes extracellular matrix
fibroblasts and stromal cells
Supports tussue for HSC and developing cells
Bone Marrow growth factors
EPO - erythropoietin - promotes RBC production in BM during hypoxia
Thrombopoietin - liver and kidney - develop megakaryocytes into PLT
Cytokines
Estrogen - erythropoiesis
Androgen - erythropoiesis via EPO production
Thyroid hormones - erythropoiesis via Hgb production
Cytokines
CSF - colony stimulating factor - myeloblasts into granulocytes
Interleukins - differntiation/maturation/immunological factors
Interferons - differntiation/maturation
HSC
Hematopoietic Stem Cells
self-renew
WBC, RBC, PLT or apoptosis
requires extrinsic and intrinsic factors for differntiation
Intrinsic factors
genetic composition of cell (genes)
Extrinsic factors
cytokines, growth hormones, hormones
Can be used as treatments for clinical application (anemia, immune)
Leukopoiesis
WBC production
myelopoiesis (granulopoiesis)
lymphopoiesis
Three pools in Bone marrow
Stem cell pool
Proliferation pool (mitotic)
Maturation pool (storage)
Stem cell pool
HSC
Proliferation pool
Mitotic
Dividing cells
CMP - common myeloid progenitor
CFU GMP - genulocyte macrophage proginetor cells
CMP/CFU - myeloid (4-6 days to mature)
Maturation pool
storage
nuclear maturation
cells ready to release into peripheral blood
metamyelocyte - segmented cell (4-6 days to mature)
Marginating pool
loosely localized to walls of capillaries
liver, spleen, lung
Circulating pool
circulating in blood vessels
How do WBC cells enter cirulation
endothelial cells lining vessels
short life span in tissues
replaced by cells in storage pool
Unused cells - apoptosis
Physiological cause of leukocytosis
non-pathological
Strenuous exercise
Emotional stress
Labour
Increased epinephrine
Pathological cause of leukocytosis
Disease process
Bacterial infection
Neoplasms (leukemia)
Acute hemorrhage
Tissue damage
Drugs/toxins
Inflammatory disorder
Granulopoiesis
Myeloblast - Promyelocyte - Myelocyte - Metamyelocyte - Band - Polymorphonuclear
granule containing WBC
innate immune system
Neutophils, eospinophils, basophils
