Inflammation and Healing Flashcards Preview

Phase 2a - Introductory Clinical Sciences > Inflammation and Healing > Flashcards

Flashcards in Inflammation and Healing Deck (94)
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61

what does association of granulomas with eosinophils indicate?

parasitic infection (e.g. worms)

62

What type of granuloma is seen in TB?

granuloma with caseating necrosis

63

what type of cells make multinucleate giant cells in granuloma?

histiocytes

64

list some common causes of granuloma

TB, leprosy, fungi, parasites, syphilis.
materials that resist ingestion - keratin, necrotic bone, talk, silica.
beryllium
Crohn's disease; sarcoidosis; Wegener's granulomatosis

65

what causes formation of histiocytic giant cells?

accumulation of matter that is indigestible by macrophages.
especially when foreign particles are too large to be ingested by a single macrophage.

66

describe the appearance of Langhans giant cells

horseshoe arrangement of peripheral nuclei at one pole of the cell - characteristic in TB

67

what type of giant cell is characteristic in TB

Langhans giant cell

68

describe the appearance of foreign body giant cells

large cells with nuclei randomly scattered throughout cytoplasm

69

what must be present for there to be a granuloma?

EPITHELIOID HISTIOCYTES - giant cells are commonly seen in granulomas, but without epithelioid histiocytes, it's not a granuloma

70

describe the appearance of Touton giant cells

central ring of nuclei, peripheral to which there is lipid material

71

list some of the roles of chronic inflammation in systemic/organ-specific diseases

myocardial fibrosis after MI.
initiation and propagation, and progression, of cancer e.g. ulcerative colitis, tissue response to asbestos fibres.
atheroma development.
tissue injury associated with neurodegenerative disorders e.g. MS

72

differentiate between resolution and repair

Resolution - initiating factor removed, tissue undamaged/able to regenerate.
Repair - initiating factor still present, tissue damaged and unable to regenerate.

73

define repair

replacement of damaged tissue by fibrous tissue.
collagen is produced by fibroblasts.

74

list types of cell that regnerate

hepatocytes
pneumocytes
all blood cells
gut epithelium
skin epithelium
osteocytes

75

what cell types don't regenerate?

myocardial cells
neurones

76

describe the appearance of coagulative necrosis

firm, pale area with ghost outlines on microscopy

77

describe the appearance of colliquative necrosis. where is this seen?

dead area is liquefied.
seen in the brain.

78

what disease shows caseous necrosis? what is the appearance of this?

TB.
pale yellow semi-solid material.

79

define gangrene, and its appearance

necrosis with putrefaction.
follows vascular occlusion or certain infections.
black.

80

what is fibrinoid necrosis?

a microscopic feature in arterioles in malignant hypertension

81

list the types of necrosis

coagulative
colliquative
caseous
gangrene
fibrinoid
fat necrosis

82

what causes fat necrosis?

trauma.
pancreatitis.

83

give an example and explanation of complete restitution

complete restoration following loss of part of a regenerative cell population - e.g. healing of a minor skin abrasion.

84

define organisation of tissues

repair of specialised tissues by formation of fibrous scar.

85

how does organisation occur?

production of granulation tissue, laid on a scaffold of fibrin, and removal of dead tissue by phagocytosis.

86

describe the formation of granulation tissue

capillary endothelial cells grow and proliferate into damaged area - open into vascular channels, arranged as loops.
fibroblasts divide, secrete collagen/matrix, and acquire bundles of muscle fibres - myofibroblasts, function as SMCs.
contract to reduce wound size.

87

what does granulation tissue consist of?

loops of capillaries supported by myofibroblasts.
possible inflammatory cells.

88

what causes wound contraction? what is its purpose?

contraction of myofibroblasts in granulation tissue. collagen is secreted, forming a scar.
reduces volume of tissue for repair - but this produces a scar

89

describe "healing by first intention"

apposed wound margins are joined by fibrin deposition, which is then replaced by collagen and covered by epidermal growth

90

describe "healing by second intention"

wound margins are unapposed due to extensive tissue damage.
tissue defect fills with granulation tissue.
epithelial regeneration to cover surface.
granulation tissue contracts - scar formation