Granulocytes Function Micro Drraj Flashcards
What are granulocytes ?
Also called
Granular leukocytes
Poly morphnuclear granulocytes ( meaning having many forms)
Name these granulocytes ?
Neutrophils Eosinophils Basophils They are released from bone marrow at 7 million cells Short lived 2-3 days
What are characteristics of neutrophils ?
Amount in curculation ?
Shape and content?
- 60-70% of WBC in circulation
More than 95% of granulocytes - Multilobed , granulated cytoplasm
What is the type of stain of neutrophils ?
What increases there production in bone marrow ?
Who is the first cell to migrate during inflammation ?
What attracks neutrophil ?
Are neutrophils found in normal tissues ?
What does neutrophils protect us against ?
What are the types of granules neutrophils have and there contents?
What is the mechanism of action of neutrophils ?
What is neutropenia and its effect ?
Both basic and acidic
Cytokines
Neutrophils
Chemokines / complement / clotting factors / bacterial products
No only in inflammed ones that they migrate to ( restricted to site of inflammation )
They are early antibacterial defenses
Primary : myeloperoxidase / lysozyme / defensins
Secondary : lactoferrin / lysozyme / defensins
Defensin antibacterial peptide
Lyzozyme nonspecific cell lysis
Lactofetrin chelate iron
1 - phagocytosis
- Release toxic granules and cytotoxic factors
- Phagocytosis + opsinization
- ADCC antibody dependent cell cytotoxicity
- Respiratory burst : away to make it more effective activating the killing mechanism of granulocytes
Neutropenia it is the decrease in neutrophils and this leads to bacterial and fungal infections which spread to blood and other tissues due to inability to limit infection
Explain : antibody dependent cell mediated cytotoxicity ?
Antibody bind target cell then attach to F cells ( neutrophils , b , e , nk ) through Fc receptor and mediate phagocytosis ( so phagocytosis occur without complements need )
From where esinophils originate from ?
What are some characteristics of e?
Percentage ?
What does the granules contain ? Contain toxic mediators list them
How is it activated ?
From the bone marrow in reposnce of t cell cytokine
They are bilobed , cytoplasmic granules with acidic stain eosin
2-5 % of circulting wbc in nonallergic reaction
Mechanism of action ?
It can phagocytose why ? Because parasite large but mainly via respiratory burst and cytotoxicty
It has an impressive respiratory burst
The granules contain peroxidase = hydroulir acid
Major basic proteins : damage parasite
Cations proteins : drill holes in the worm
Cytokines / chemokines / via igE receptor where ige receptor in esinophil bind to ige and crosslinking occurs
What is the percentage of basophils ?
What type of granules and how are they stained ?
How they attack pathogens ?
How are they reqruited ?
What are basophils in tissue ?
What happens to mast cells during worm infestation ?
What does mast cells degranulate and why ?
Less than 0.2 %
Basophillic and stained by methalene blue
Non phagocytic by releasing active substance including Histamin( increase permiability and vasodilator )
By cytokines
Mast cells simialer to basophils non phagocytic
Originate in bone martow but found only in tissue
So they are home to normal tissues such as submucosa skin connective tissue
Increase reqruiment by also cross linking ige the degranulation
What are the functions of granulocytes ?
- Phagocytosis
- Cytotoxicity
- Opsonization
- Inflammation
- Respiratory burst
Explain phagocytosis ?
Main function : to clear bacteria , protozoa , fungi
Phagocytosis = internalization of particulate matter
Phagocytes contain lysosomes =
What is respiratory burst ?
First u should know that the phagocytes are live resting not doing a thing in order for them to do something they need to be activated
When activated , phagocytes generate hydrogen peroxide and other metabolites including definsin lysozyem
So respiratory burst is = increase in oxidative metabolism of phagocytes after uptake of opsonized particles = reactive oxygen intermediates
In respiratory burst 3 enzyme pathway activated and they are ? Hydrogen peroxide
Hypochlorous acid
Nitric oxide
What is cytotoxicity?
Eosinophils and mast cells kill worms in the gut
Neutrophils = granules and cytotoxic substance
Eosinphils perform cytotoxicity via release of granules
Enosiphils granules : peroxidase hypochlorous
Major basic proteins and cationic protein
What is opsonization ?
Making bacteria more attracted to macrophages and neutrophils
Making it easier for phagocytes to bind bacteria ?
Via fc receptor that bind to ab on bacteria
Via complement receptors that bind to complement that are bound to bacteria
How inflammation starts ?
Starts with migration of granulocytes and monocytes to site of infection
Local macrophage detect oinfection recruit neutrophils to site of inflammation
How attarcted by
Cytokines chemokines clott bacterial products
Machrophage release cytokines signal to produce neutrophils in marrow chemotaxis of neutrophils tos itevof infection neutrophils and endothelium express afhesion molecule neutrophils adhere to endothelium and squeezw between cells and enter site of infection
Neutrophils get activated during inflammation thisvleads to respiratory burst increase production of mediators roi rni granule content thus increase killing of pathogens
