5. Chronic inflammation Flashcards
What are the 5 features of chronic inflammation?
Delayed onset Variable duration Variable appearances Limits damage, initiates repair Can cause debilitating symptoms
How does chronic inflammation arise?
Takes over from acute inflammation (of resolution not possible with acute inflammation)
Develops alongside acute inflammation
Arises ‘de novo’ (without preceding acute inflammation)
What are the white areas in phagocytes?
Phagolysosome
What do phagocytes look like?
Large cells
Abundant foamy cytoplasm
Sometimes indented nuclei
All look different (inconsistent) as depends on what they phagocytose
What is the function of macrophages?
Phagocytosis - removal of pathogen/necrosis/debris, antigen presentation to immune system
Inflammatory mediators - synthesis and release of many mediators, controls and regulates inflammatory response
What do lymphocytes look like?
Small cells
Slightly larger than RBC
Large spherical nucleus - very thin rim of cytoplasm
What is the role of T cell lymphocytes?
Helper - assist other inflammatory cells (CD4+)
Cytotoxic - destroy pathogens (CD8+)
What is the role of f B cell lymphocytes?
Mature into plasma cells
Produce antibodies
Neutralise pathogens
What do plasma cells look like?
Eccentric nucleus (not central)
‘Clock-face’ chromatin (clumps, line up around edge of nucleus)
Peri-nuclear clearing (paler area around nucleus) - Golgi
What is the function of plasma cells?
Fully differentiated B lymphocyte
Produces antibodies
What do eosinophils look like?
Bi-lobed nucleus
Granular cytoplasm stains red
Granules full of chemical mediators
What is the function of eosinophils?
Release of a variety of mediators
Role in hypersensitivity reactions and parasitic infections
What is the role of fibroblasts/myofibroblasts?
Regeneration and repair
Create and lay down collagen
What are giant cells?
Multinucleate cells
Fusion of multiple macrophages
Increases effectiveness of phagocytosis
What are the 3 types of giant cells?
Foreign body giant cell
Langhans giant cell - nuclei line up around edge of cell (can be seen in TB)
Toulon giant cell - nuclei line up in circle in centre of cell (can be seen in fat necrosis)
What cells are predominant in rheumatoid arthritis?
Mainly plasma cells
What cells are predominant in chronic gastritis?
Mainly lymphocytes
What cells are predominant in leishmaniasis (protozoal infection)?
Mainly macrophages
What are the effects of chronic inflammation?
Fibrosis (deposition of collagen)
Impaired function (rarely increased function e.g. Graves’ disease)
Atrophy
Stimulation of immune response (antigen presentation)
Describe Crohn’s disease
Can affect all of GI tract
Discontinuous patches of inflammation (skip lesions)
Inflammation affects full thickness of bowel wall causing strictures and fistulae
Can sometimes find granuloma
Describe ulcerative colitis
Affects large bowel only Continuous inflammation Inflammation affect superficial bowel wall only No granuloma More likely to have rectal bleeding
Why does liver cirrhosis occur?
End stage damage to liver due to alcohol, hepatitis, drugs and toxins, fatty liver disease
Fibrosis and attempted regeneration causes lumps on surface of liver
What is granulomatus inflammation?
Chronic inflammation and granuloma
What is a granuloma?
A collection of epithelioid histiocytes (macrophages that look like epithelial cells), with surrounding lymphocytes
Often has caseous necrosis inside
