Leucopoiesis Flashcards
What is the shape of a promyelocyte?
Circular; as matures a band structure forms.
What is the differentiating factor between band neutrophils and monocytes?
Band neutrophils are granular.
Monocytes have vacuoles and lack granules.
What are the growth factors involved with the development of the promyelocyte?
Stem cell factors
GM - CSF
G - CSF
Interluekin 3
What is the point of increased granulocyte activity during gestation?
after 4-5 months
Where does the transformation of the myeloblast to the mature granulocyte occur?
How long does it take?
The myeloblast forms in the marrow, then turns into the mature granulocyte in the peripheral blood
6-10 days.
Which wbc make up the granulocytes?
Basophils and eosinophils and neutrophils
Describe the shape/conformation of the mature neutrophil.
2-3 times the size of healthy red cell
nucleus divided into 2-5 lobes separated by a thin strand or filament of nuclear filament.
Chromatin lumpy
cytoplasm = pale blue/lilac stained granules
What is the normal reference range for the absolute no. of neutrophils?
2 - 7 x10^9/L
40-75% of wbc
What do female neutrophils have that males do not?
Females - have small lobe called the drumstick - inactive X chromosome.
What are the 6 enzymes in the pink/lilac staining granules in neutrophils?
(ALL HAM) Acid phosphatase Lactoferrin Lysozyme Hydrolases Alkaline phosphatase Myeloperoxidase.
What are mature neutrophils very dependent on in terms of energy?
On glycolysis and ATP production
What is the most common leukocyte and where are they?
Neutrophil;
Half total blood granulocyte are in the CGP (circulating granulocyte pool)
Remainder are in the marginal pool (MGP)
What is the MGP associated with?
The loose adherence of leukocytes to the vascular endothelium and tissues.
How long do neutrophils spend in the blood ?
Neutrophils spend only on average 10 hours in the blood before passing into the tissues.
What accelerated the migration of neutrophils from the blood to the tissues?
Damage or local inflammation.
What are the 4 ways in which neutrophils play a role in the killing of bacteria and fungi?
Chemotaxis
Opsonization/adhesion
Ingestion/phagocytosis
Killing phase
What is the role of chemotaxis and neutrophils in the killing of bacteria?
N react to specific chemical stimuli called chemotaxins which direct the neutrophils to the site of infection.
What are the four chemotaxis activations ?
coagulation (bleeding)
complement (innate immune response)
fibrinolytic (breaks down fibrin)
Kinin (pain)
What is the role of neutrophil opsonization in bacteria killing?
This is where the surface of the bacteria is modified to allow neutrophil binding for phagocytosis via specific receptors.
What is the role of phagocytosis via neutrophils in bacteria killing?
This is the ingestion of the pathogen through enclosing it in a vacuole and eating via enzymes and proteins in the granules to kill the pathogen.
What are the main stages and enzymes involved in the killing phase of bacteria by neutrophils?
Both oxygen dependent and oxygen independent systems involved.
Different proteins and enzymes, both result in killing bacteria.
Myeloid Peroxidase and lysozyme.
Which enzyme(s) are involved in the oxygen dependent system of killing bacteria?
Myeloidperoxidase, H2O2 = superoxide and hydroxyl radical formation.
Which enzyme(s) are involved in the oxygen independent system of killing bacteria?
Direct action of lysozyme - fall in pH to activate, attacks cell wall of bacteria and bactericidal property of cationic proteins from primary neutrophil granules.
What molecules are involved in the process allowing neutrophils to bind to their vascular endotheial cells?
Integrins and selectins - these facilitate N movement through the vascular endothelial cells to the tissue
