Granulopoiesis Flashcards
when and where does granulopoiesis occur
bone marrow after 4-5 months gestation
what is granulopoiesis?
the maturation of myeloblast to granulocyte which takes 6-10 days
what are the granulocytes?
neutrophils, eosinophils, basophils
what is the reference range for neutrophils?
2-7 x10>9 /L
what enzymes do neutrophils contain?
myeloperoxidase, alkaline phosphatase, acid phosphatase, hydrolase, lactoferrin and lysozyme
where do neutrophils get energy?
ATP from glycolysis
what is the function of neutrophills?
kill bacteria and some fungi
what are the steps in neutrophils killing bacteria?
- chemotaxis
- opsonisation
- phagocytosis
- killing
what is opsonisation?
bacteria surface modified, immune adherance - bacteria bound to neutrophil membrane
what is chemotaxis?
chemotaxins (proteins derived from plasma protein pathways) direct neutrophils to site of infection
how do neutrophils phagocytose bacteria?
enclose in phagocytotic vacuole into which granules are discharged
what are the stages in bacteria killing?
- oxygen dependent: myeloperoxidase, hydrogen peroxide, superoxide, hydroxyl radical formation
- oxygen independent; fall in pH, lyzozyme attach cell wall, cationic proteins
when are primary granules formed?
promyelocyte stage
what do primary granules contain?
Myeloperoxidase Bacterial permeability inducing factor Lysozyme Elastase Acid hydrolases
what does myeloperoxidase do?
non specific converts h202 to hypochlorus acid which has antimicrobial properties
what does bacterial permeability inducing factor do?
binds to LPS (targets gram neg) to increase membrane permeability
what does lysozyme do?
degrades bacterial cell wall
what does elastase do?
targets gram neg, fungi and enterotoxins
what do the secondary granules provide?
the distinctive staining patterns that are used in the identification of granulocytes and their precursors
what do the secondary granules contain?
Lactoferrin which has bacteriostatic and bactericidal
Lysozyme is also found in the secondary granules as well as the primary granule
what do the Tertiary granules include?
gelatinase which is capable of digesting denatured collagen as well as intact collagen
what does digestion by gelatinase allow?
neutrophils to migrate through the blood vessels basement membrane and enter tissue fluid
