Flashcards in Inflammation and Healing Deck (94)
what does association of granulomas with eosinophils indicate?
parasitic infection (e.g. worms)
What type of granuloma is seen in TB?
granuloma with caseating necrosis
what type of cells make multinucleate giant cells in granuloma?
list some common causes of granuloma
TB, leprosy, fungi, parasites, syphilis.
materials that resist ingestion - keratin, necrotic bone, talk, silica.
Crohn's disease; sarcoidosis; Wegener's granulomatosis
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.
describe the appearance of Langhans giant cells
horseshoe arrangement of peripheral nuclei at one pole of the cell - characteristic in TB
what type of giant cell is characteristic in TB
Langhans giant cell
describe the appearance of foreign body giant cells
large cells with nuclei randomly scattered throughout cytoplasm
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
describe the appearance of Touton giant cells
central ring of nuclei, peripheral to which there is lipid material
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.
tissue injury associated with neurodegenerative disorders e.g. MS
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.
replacement of damaged tissue by fibrous tissue.
collagen is produced by fibroblasts.
list types of cell that regnerate
all blood cells
what cell types don't regenerate?
describe the appearance of coagulative necrosis
firm, pale area with ghost outlines on microscopy
describe the appearance of colliquative necrosis. where is this seen?
dead area is liquefied.
seen in the brain.
what disease shows caseous necrosis? what is the appearance of this?
pale yellow semi-solid material.
define gangrene, and its appearance
necrosis with putrefaction.
follows vascular occlusion or certain infections.
what is fibrinoid necrosis?
a microscopic feature in arterioles in malignant hypertension
list the types of necrosis
what causes fat necrosis?
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.
define organisation of tissues
repair of specialised tissues by formation of fibrous scar.
how does organisation occur?
production of granulation tissue, laid on a scaffold of fibrin, and removal of dead tissue by phagocytosis.
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.
what does granulation tissue consist of?
loops of capillaries supported by myofibroblasts.
possible inflammatory cells.
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
describe "healing by first intention"
apposed wound margins are joined by fibrin deposition, which is then replaced by collagen and covered by epidermal growth