Inflammatory Cells Flashcards

1
Q

What are 5 acute inflammation effector cells?

A
  • vascular endothelial cells
  • neutrophils
  • mast cells/basophils
  • eosinophils
  • monocytes/macrophages
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2
Q

Vascular endothelial cells

A

Inflammation

  • contraction
  • release of chemical mediators (NO)
  • expression of adhesion molecules and receptors
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3
Q

Leukocytes

A
  • neutrophils
  • eosinophil
  • basophil/mast cell
  • monocyte/macrophage
  • lymphocyte/plasma cell
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4
Q

What is the avian equivalent of a neutrophil?

A

Heterophil

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5
Q

Neutrophil cell characteristics

A

Segmented nucleus, multiple complex granules

  • recruited by IL-8!!
  • short lived –> 24 hrs in circulation, 1-2 days in tissue
  • aka: polymorphonuclear leukocytes
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6
Q

Neutrophil function

A

Innate immunity to bacteria and fungi

  • phagocytosis
  • release of granular contents
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7
Q

What are the 3 phases of neutrophil phagocytosis?

A
  • attachment to particles to the cell surface
  • ingestion of particles
  • breakdown of particles
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8
Q

_______ greatly facilitates phagocytosis

A

Opsonization

- via IgG antibodies and complement

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9
Q

Neutrophil granules

A
  • myeloperoxidase: converts H2O to hypochlorous acid which is toxic to microbes
  • lysozyme
  • antimicrobial substances
  • gelatinase: break dwon tissue
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10
Q

Enzymes released cause _____ of the exudate and accumulation of pus

A

Liquefaction
- **reptiles and birds have reduced concentration of enzymes and cannot liquefy the exudate, leading to formation of caseous material

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11
Q

Neutrophil extracellular traps

A

Extracellular fibrillary networks that provide high concentrations of antimicrobial substances

  • trap microbes to prevent spread
  • meshwork of nuclear chromatin that binds and concentrates antimicrobial peptides and enzymes
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12
Q

Neutrophil production and maturation takes place in the _______

A

Bone marrow
- cytokines stimulate endothelial cells and fibroblasts to produce colony stimulating factors —> CSFs act directly on hematopoietic subpopulations in bone marrow to increase cellular proliferation/differentiation –> release from bone marrow is orderly and age-related with mature segmented cells released first

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13
Q

Eosinophils

A

1-5% of WBCs

  • short lived –> 12 hrs in circulation, 1 week in tissue
  • emigrate from blood and live in subepithelial sites in skin, lung, GIT, and endometrium
  • enter lesions during transition from acute to chronic inflammation!!!
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14
Q

What attracts eosinophils?

A

Histamine, eosinophil chemoattractant factor A (mast cells), eotaxin

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15
Q

Eosinophil function

A
  • innate immunity to parasites
  • associated with allergies to hypersensitivity
  • modulate local immune responses = production and release of cytokines
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16
Q

Eosinophil cell characteristics

A
  • bilobed nucleus
  • cytoplasmic granules
  • major basic protein, lysosomal enzymes and peroxidases (less effective than neutrophils)
  • result in major tissue damage (collagenolysis)
17
Q

Eosinophilic exudate

A

Chronic

- green tinge to muscle

18
Q

Mast cells/basophils

A

Found in all supporting tissues

  • distributed in skin, GIT, and blood vessels (rapid response)
  • long lived (4-12 weeks)
  • replicate in tissue!!
  • deeply basophilic granules and condensed nucleus
19
Q

Metachromatic granules of mast cells

A
  • histamine
  • eosinophil chemotactic factor
  • heparin
  • synthesize prostaglandins, leukotrienes and PAF
  • proteolytic enzymes (tryptase)
20
Q

Mast cells express high affinity receptors for ______ on suface

A

IgE

  • stimulated by cross linking of IgE
  • fusion of cytoplasmic granules which then fuse with the plasma membrane and exit thru a pore
  • immune system must be primed!!!
21
Q

Immediate response of mast cell degranulation

A
  • vasodilation
  • vascular leakage
  • smooth muscle spasm
22
Q

Late phase reaction of mast cell degranulation

A
  • leukocyte infiltration
  • epithelial damage
  • bronchospasm
23
Q

Monocytes and macrophages

A

Originate in bone marrow, migrate in blood for 6 days and settle in tissues as macrophages

  • monocytes are short lived in circulation
  • macrophages are long lived in tissues, retain ability to proliferate
24
Q

Monocyte/macrophage function

A
  • phagocytosis
  • antigen presentation
  • immune modulation
25
Q

Monocyte cell characteristics

A

Large nucleus with indentation, multiple granules and vacuoles
- granules are similar to primary neutrophilic granules

26
Q

What are the 2 types of macrophages?

A
  • those that reside within a specific tissue (physiologic)

- those derived from monocytes in response to a stimulus

27
Q

Tissue macrophages

A
  • kupffer cells (liver)
  • microglia (CNS)
  • alveolar macrophages (lung)
  • langerhans cells (skin)
  • osteoclasts (bone)
28
Q

Macrophages recruited to inflammation

A

Respond by chemotaxis

  • arrive as a second wave after neutrophils (12-48 hrs) take over
  • antigen processing and presentation
  • engulf and destroy tissue debris and foreign material (less efficient than neutrophils)
  • modulate immune response via release of cytokines!!
29
Q

How do macrophages destroy tissue and foreign material?

A
  • release of lysosomal enzymes
  • free radicals
  • opsonization enhances phagocytosis
30
Q

______ are one of the main triggers of the adaptive immune response

A

Macrophages

31
Q

Platelets

A

Biconvex discs

  • arise from megakaryocyte fragmentation in marrow
  • hemostasis control
  • deliver inflammatory mediators to injured sites
  • preformed substances in granules (histamine)
  • chemokines involved in chemotaxis (platelet activating factor)
  • thromboxane A2 (vasoconstriction)
  • growth factors