Haematopoiesis Flashcards
Haematopoiesis what
Process by which mature blood cells are generated from precursor cells
Conc and % for RBC, platelet, WBC
RBC-4-6x106/microlitre 45%
Platelet-~1.5-4x105/microlitre
WBC=~4-11x103/microlitre
Prenatal and post natal haematopoesis location
Prenatal=yolk sac, liver, spleen, bone marrow, lympth nodes
Postnatal=tibial,femur, lymph nodes, ribs, sternum, vertebral+pelvis
Define: totipotent, pluripotent, multipotent, unipotent/progenitor
Totipotent=stem cell that is able to produce all the differentiated organisms
Pluripotent=stem cell that can divide into either the endoderm, mesoderm, ectoderm
Multipotent=stem cell that has the ability to divide into multiple but restricted cell types
Unipotent/progenitor: restricted to single lineage. Multiplification is lineage-specific growth factors. Does not have potential for self renewal
Draw flow chart of stem cell, progenitor cells, precursor cells and blood tissue
ref. notes
Draw macrostructure bone marrow
ref. notes. Haematopoesis occur between sinuses
Blood cell differentiation draw out
ref. notes
erythrocyte precursor where. RBC removedwhere
erythrocyte precursor=cells in bone marrow
Old RBC=spleen and liver
RBC how produced
Normoblast (prenultimate precursor) eject nucleus and form reticulocyte. Takes 1-2 days for remaining RNA and organelles to be lost
Platelet where produced, describe shape, function
where-BM (limited de novo) from megakaryocyte precursors via thrombopoeitin
shape-anuclear, discoid, 2-4micrometre diameter 8-12 days
function-haemostasis nad maintenance of blood vessels. Attach to fibrin filaments and damaged endothelial surfaces
Megakaryocyte what
responsible for platelet production.The cytoplasm in giant cells partitioned into packages by vesicles of ER. Vesicles of ER fuse ejecting platelets
Neutrophil traits
predominant circulating leukocyte 60%, 10^11 produced and released from bone marrow. polymorphonuclear=no ability to multiply, little capacity for protein synth. Highly motile, respond rapidly to chemotactic substances. First cell type recruited to site of inflammation
what gives traction for neutrophil motility
uropod
Eosinophil traits
rare circulating leukocyte under basal conditions, bi lobed nucleus, motile to various chemoattractants, extracellular killing of parasites, eosinophil associated gut diseases, hypereosinophilic syndromes
Eosinophil morphology
major basic protein: very highly cationic, toxic towards helminthic parasites, tissue damage to host
eosinophil cationic protein: bacteriocidal, promotes mast cell degranulation
eosinophil derived neurotoxin: antiviral activity in respiratory infection
Eosinophil peroxidase: catalyses teh peroxidation of halides and hydrogen peroxide. Bacteriocidal tissue damage to host
Eosinophil how long last for
leave circulation after 8-12 hours of release from bone marrow. Lifespan in tissues~several days. Number increase greatly in parasitic infections and some allergic states.
Monocytes trait
largest leukocyte, nucleus - horseshoe or kidney shape, highly phagocytic and motile
Functions of macrophages
- Defence against microorganisms
- Refuse collection
- antigen presentation
- cytokine secretion (important in regulation of haemopoiesis)
Lymphocytes types and traits
small lymphocytes: 6-9 micrometre in diameter, condensed nucleus 90% of cell, thin rim of cytoplasm
large lymphocyte: 9-15 micrometre diameter, mostly activated B cells in transit to tissues to become plasma cells
NK cells: thesecan kill some virus infected or tumour cells by mechanism not involving specific antigens
What do B and T lymphocytes have on the surface and give function
B lymphocytes: have surface immunoglobulin (receptor), respond to antigen by proliferating and maturing into plasma cells which then secrete the same immunoglobulin (antibody)
T cells have receptors for antigen
Helper=express the CD4 marker on surface, respond to antigen by secreting cytokines that help other lymphocytes
Cytotoxic=express CD8 markers on surface, kill virus infected cells
