Download blood-inter-04

Histology of blood cells
• Jeanne Adiwinata Pawitan
• Department of Histology FMUI
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Blood – 5 lt
• Specialized connective tissue – circulate –
logistical support, communication
• Component:
° Blood plasma - serum
° Cells
• Erythrocytes (45%)
• Leucocytes – (polymorphonuclear,
mononuclear)
° Platelets
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1%
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
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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-blueblack)-pressed to periphery →rough
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Azurophilic granules
• = lysosomes contain:
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Acid hydrolase
Myeloperoxidase
Lysozyme (antibacterial agent)
Bactericidal permeability increasing (BPI)
protein
° Cathepsin G
° Elastase, Nonspecific collagenase
→ extracellular matrix →tissue damage
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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
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Neutrophil’s specific granules
• Small specific granules:
° Enzymes
° Pharmacological agent
antimicrobial function
facilitate migration
• Tertiary granules-neutrophil chemotactic
agent→release:
° Gelatinase-degrades basal lamina - facilitate migration
° Cathepsins
° Glycoproteins – inserted to plasmalemma – facilitate
phagocytosis
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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
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Phagocytosis
Phagocytosis
↓
phagosome
→
(intracellular vacuole)
destroyed
ingested microorganism
↑
Azurophilic granules (lysosome)
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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)
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•
< 4 % - total leucoØ 10-14 μm
Nucleus – bilobe
Plasmalemma rec binds to
° Histamin
° Leucotrienes
° Eosinophil
chemotactic factor
release by mast cells,
baso-, neutroJeanne A Pawitan
Eosinophils
→ 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
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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
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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)
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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
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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
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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 >>>
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Lymphocyte
Size
• Small Ø 8-10 μm
• Medium Ø 12-15μm
less numerous
• Large Ø 15-18μm
Type (functional)
• B lymphocytes – 15 % - months immuno
• T lymphocytes - 80 % - years
cytochem
• Null cells
(surface
markers)
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Lymphocyte functions
• In connective tissue (not in blood)
° Immune system
• B lymphocyte – bone marrow
• T lymphocyte – thymus (cortex)
immunocompetent
(maturation) →lymphoid system →mitosis →clone
 Memory cells – ready for subsequent Ag chalenge
 Effector cells → respond to Ag
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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
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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
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Monocyte
ME
• Cytoplasm
° Organels
° Periphery
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Microtubules
Microfilaments
Pinocytotic vesicles
Filopodia
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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
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Platelets/thrombocyte/thromboplastids
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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
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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?
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Platelets – EM - granulomere
• Few organels
° Mitochondria
° Peroxisomes
• Glycogen deposits
• Enzymes
° Catabolize glycogen
° Consume O2
° Generate ATP
• Granules (α, δ, λ)
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Platelets - granules
• α granules – 300-500 nm –contains
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Fibrinogen
Platelet derived GF
Platelet thromboplastin
Thrombospondin
Coagulation factors
• α granules content → facilitate
° Vessel repair
° Platelet aggregation – blood coagulation
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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
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Platelets - functions
• Injury → limit hemorrhage
° Platelets → activated
° Tissue factors - plasma born factors –
platelet derived factors → blood clot
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Normal
• Endothelium intact –
inhibit platelet aggr.
° Prostacyclins
° NO2
• Endothelium luminal
plasmalemma –
inactivate specific
coagulation factor
° Thrombomodulin
° Heparin – like
molecule
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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
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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)
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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
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Thrombus (blood clot)
Contraction
• Actin monomers →
thin filaments
• Myosin monomers →
thick filaments
• ATP – actin-myosin
filaments interact →
contraction
Lysis
• Vessel repaired →
endothelium –
plasminogen activators
plasminogen → plasmin
+ λ gr. enzymes
lysis of thrombus
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