Jeanne A Pawitan Histology of blood cells Jeanne Adiwinata Pawitan Department of Histology FMUI.
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Transcript of Jeanne A Pawitan Histology of blood cells Jeanne Adiwinata Pawitan Department of Histology FMUI.
Blood – 5 lt
• Specialized connective tissue – circulate – logistical support, communication
• Component:° Blood plasma - serum° Cells• Erythrocytes (45%)• Leucocytes – (polymorphonuclear,
mononuclear) 1%
° Platelets
Leukocytes
• Polymorphonuclear (granular→ granulocyte)° Basophilic leukocytes (basophils)° Eosinophilic/acidophilic leukocytes (eosinophils)° Neutrophilic/heterophilic /polymorphonuclear
leukocytes (neutrophils, polys)
• Mononuclear (agranular→ agranulocyte)° Monocytes ° Lymphocytes• B lymphocytes• T lymphocytes
Leucocyte granules• Nonspecific (azurophilic) granules–0.5μm
- all leucocytes• Specific granules – Giemsa/Wright° Neutrophils • Small specific granules (0.1 μm– light pink)• Tertiary granules
° Eosinophils – specific granules (oblong:1-1.5 μm >< 1 μm ) - dark pink
° Basophils –specific granules (0.5 μm-blue-black)-pressed to periphery →rough
Azurophilic granules• = lysosomes contain:° Acid hydrolase° Myeloperoxidase° Lysozyme (antibacterial agent)° Bactericidal permeability increasing (BPI)
protein° Cathepsin G° Elastase, Nonspecific collagenase
→ extracellular matrix →tissue damage
Neutrophils
• Most numerous → 60-70 % total leuco-
• Ø 9-12 μm (in blood smears)
• Nucleus ° multilobes – chromatin threads, age ↑- lobe↑° ♀- drumstick/Barr body - condensed,
inactive, 2nd X chromosome
• ↑- acute bacterial infection
Neutrophil’s specific granules
• Small specific granules:° Enzymes antimicrobial function
° Pharmacological agent facilitate migration
• Tertiary granules-neutrophil chemotactic agent→release: ° Gelatinase-degrades basal lamina - facilitate migration
° Cathepsins
° Glycoproteins – inserted to plasmalemma – facilitate phagocytosis
Neutrophil’s function
• Phagocytosis – microorganism → microphage• Kill bacteria by° Enzymes° Forming reactive Oxygen compounds
→ die → (dead leuco, bacteria, tissue fluid)• Synthesize leucotrienes (from arachidonic
acid-in their cell membrane) – aid in initiation of inflamation
Phagocytosis
Phagocytosis
↓
phagosome → destroyed(intracellular vacuole) ingested microorganism
↑
Azurophilic granules (lysosome)
Reactive oxygen compounds
• Superoxide - formed in respiratory burst (by NADPH oxidase)
• Hydrogen peroxide formed from superoxide (by superoxide dismutase)
• Hypochlorous acid (HOCP) formed from hydrogen peroxide and chloride ions (by myeloperoxidase)
Eosinophils• < 4 % - total leuco-• Ø 10-14 μm• Nucleus – bilobe• Plasmalemma rec -
binds to ° Histamin
° Leucotrienes
° Eosinophil chemotactic factor
release by mast cells, baso-, neutro-
→ Migrate to site of° Allergic reaction
° Parasitic worm invasion
° Inflammatory reaction
Eosinophil’s specific granules
• EM: ° center (=internum) – crystal like –electron
dense – contains:• Major basic protrein form pores in• Eosinophilic cationic protein parasites’ pellicle• Eosinophil derived neurotoxin
° Externum – less electron dense- contains:• Histaminase• Peroxidase, & other enzymes
Eosinophil’s function
• Kill parasites-by facilitating access of superoxide, hydrogen peroxide via pores in pellicles
• Release histaminase & other substances → inactivate initiators of inflamation° Histamine
° Leucotriene C
• Engulf Ag-Ab complex → endosomal compartment → degradation of Ag-Ab complex
Basophils
• < 1% total leuco-
• Ø 8-10 μm
• Nucleus – S shaped – masked by specific granules
• Plasmalemma – surface receptors – e.g. Ig E receptors → binds IgE (from plasma cells)
Basophil’s specific granules
• Specific granules contain:° Heparin° Histamine • Vasodilation
• Smooth muscle contraction (in the bronchial tree)
• Leakiness of blood vessels
° Eosinophil chemotactic factor° Neutrophil chemotactic factor° Peroxidase
Basophil’s functions
• IgE – Ag →° content of specific granules released° Phospholipase - phospholipids (in
plasmalemma) → arachidonic acids → leukotrienes C4, D4, E4 (=slow reacting substance of anaphilaxis, SRS-A) → • similar effects with histamine, but the action is
slower, and more persistent
• Activate leuco- →migrate to site of Ag challenge
Lymphocyte • 20-25% - total leuco-• Blood smears° Round, pleomorphic – conective tissue° Nucleus • round –slightly indented – occupies most of the cell• acentrically located • dense- heterochromatin>>>
° Cytoplasm – light blue • azurophilic granules = lysosomes• Mitochondria-few, Golgi App- small, RER-few,
ribosomes >>>
Lymphocyte
Size • Small Ø 8-10 μm• Medium Ø 12-15μm less numerous• Large Ø 15-18μmType (functional)• B lymphocytes – 15 % - months immuno• T lymphocytes - 80 % - years cytochem• Null cells (surface
markers)
Lymphocyte functions
• In connective tissue (not in blood)° Immune system• B lymphocyte – bone marrow immuno-
• T lymphocyte – thymus (cortex) competent
(maturation) →lymphoid system →mitosis →clone Memory cells – ready for subsequent Ag chalengeEffector cells → respond to Ag
Effector cells• B cells diff→ plasma cells - Ab• T cells – cellular immune system diff →° Cytotoxic T cells (CTL, T killer cells) – contact –
kill• Foreign cells• Virally altered cells
° T suppressor cells →signaling molecules° T helper cells (cytokines, lymphokines) Suppression/→specific response of other cells in
immnune system
Monocyte • 3-8% -total leuco-• 12-15 μm • Circulation – few days → connective tissue -
macrophage• Nucleus- large, acentric, kidney shaped° Chromatin network- coarse – 2 nucleoli →moth
eaten/soap buble appearance
• Cytoplasm – bluish gray° Azurophilic granules
° Vacuole-like spaces
Monocyte
ME
• Cytoplasm ° Organels ° Periphery• Microtubules
• Microfilaments
• Pinocytotic vesicles
• Filopodia
Monocyte-functions• →macrophage° Phagocytosis - phagosome – enzymatic digestion,
superoxide formation→ destruction• Cells (dead, defunct)
• Ag
• Foreign particulate matter (bacteria)
° APC – epitope (most Agnic) + class II HLA/MHC
° →foreign body giant cells – large foreign particle
° Cytokines• activate inflamatory response
• → proliferation, maturation of other cells
Platelets/thrombocyte/thromboplastids
• 250,000-400,000/mm3 blood• Life span < 14 days• Disk shaped - Ø 2-4μm • Cytoplasmic fragment–megakaryocyte-bone marrow• LM° Hyalomere – periphery - clear
° Granulomere - central – darker
• Plasmalemma° Glycocalyx (15-20 nm)
° Receptor molecules
Platelets – EM - hyalomere
• 10-15 microtubules (MT)-parallel → a ring – diskoid morphology
• Actin, myosin monomers – associated to MT – assembly →contractile apparatus
• Tubular system• Surface opening (connecting) – molecule rapid
uptake & release from activated platelets
• Dense tubular system – sequester Ca? >< platelet stickiness?
Platelets – EM - granulomere• Few organels° Mitochondria ° Peroxisomes
• Glycogen deposits• Enzymes ° Catabolize glycogen° Consume O2° Generate ATP
• Granules (α, δ, λ)
Platelets - granules
• α granules – 300-500 nm –contains° Fibrinogen° Platelet derived GF° Platelet thromboplastin° Thrombospondin° Coagulation factors
• α granules content → facilitate ° Vessel repair° Platelet aggregation – blood coagulation
Platelets - granules
• δ granules (dense bodies) – 250-300 nm - contains° Ca, ADP, ATP platelet aggregation ° Serotonin, histamine & adhesion, blood ° Pyrophosphatase coagulation
• λ granules (lysosomes) – 200-250 nm – contains ° hydrolytic enzymes →clot resorption
Platelets - functions
• Injury → limit hemorrhage ° Platelets → activated° Tissue factors - plasma born factors –
platelet derived factors → blood clot
Normal • Endothelium intact –
inhibit platelet aggr.° Prostacyclins
° NO2
• Endothelium luminal plasmalemma – inactivate specific coagulation factor° Thrombomodulin
° Heparin – like molecule
Injury• Endothelium° Stop producing
inhibitors
° Von Willebrand factor →platelet activation
° Tissue thromboplastin
° Endothelin→vasoconstr
• Endothelial disruption → platelet - collagen → platelet activated → → → → → → blood clot
Platelet - activated• Content of granule – released ° ADP platelet - sticky
° thrombospondin
→Platelet adhesion (to damaged vessel wall)
→Platelet aggregation o Plug – block hemorrhage
o Plasmalemma - platelet factor 3 = phospholipid surface – assembly of coagulation factors esp. thrombin
• Arachidonic acid (plasmalemma)→ thromboxane A2 ° Potent vasoconstrictor
° Platelet activator
Cascade of reactions in clot formation
Platelet & tissue thromboplastin
↓
Prothrombin → thrombin (enzyme)→pl aggr
+ Ca
Fibrinogen → fibrin –reticulum of clot
+blood cells, platelets
blot clot (thrombus)
Thrombus (blot clot) formation
• Erytrhrocytes – facilitate – platelet activation
• Neutrophils limit platelet activation• Endothelium & thrombus size• After clot formation ° 1 hour → clot contraction – ½ size → pulling
edges → minimize blood lost° Repair of blood vessel → lysis of thrombus