Chronic Inflamation Flashcards
What is chronic inflammation?
Chronic response to injury with associated fibrosis
Know less about it at cellular/molecular/signalling level than acute
What are 2 ways call injury leads to tissue repair?
Acute insult -> acute inflammation -> if damage is slight resolution is possible
-> if damage is not slight CHRONIC INFLAMMATION - repair and scarring
OR
Chronic insult -> chronic inflammation -> repair and scarring
Ie skipping the acute phase - de novo
How does chronic inflammation arise?
- May take over from acute inflammation if damage is too severe to be resolved within a few days
- May arise de novo
– Some autoimmune conditions (e.g. RA)
– Some chronic infections (e.g. viral hepatitis)
– “chronic low-level irritation” - May develop alongside acute
inflammation …in severe persistent or repeated irritation
What does chronic inflammation look like?
• What does it look like?
– Characterised by the microscopic appearances which are much more variable than acute inflammation.
– Most important characteristic is the type of cell present.
What cells are important in chronic inflammation?
Macrophage
• Derived from blood monocytes - monocyte = circulating, macrophage = in tissue (same thing)
• Important in acute and chronic inflammation
• Various levels of activation - not activated until tissue is injured. Long lived whereas polymorphs are short lived
What are the unctions of macrophages?
– Phagocytosis and destruction of debris & bacteria
– Processing and presentation of antigen to
immune system
– Synthesis of not only cytokines, but also complement components, blood clotting factors and proteases
– Control of other cells by cytokine release
Describe the appearance of macrophages lymphocytes neutrophils and eosinophils
Macrophages - large in comparison to erythrocytes, kidney shaped nucleus off to one side
Lymphocytes - large nucleus, not much cytoplasm
Neutrophils - multi lobed nucleus,
Eosinophils - bilobed nucleus, darker stained colour
Briefly, what are the functions of lymphocytes?
Functions:
– Complex, mainly immunological.
– B lymphocytes differentiate to produce antibodies.
– T lymphocytes involved in control & some cytotoxic functions.
Name 3 other cell invoved in the chronic inflammatory response
• Plasma cells:
– Differentiated antibody-producing B lymphocytes.
Usually implies considerable chronicity.
• Eosinophils:
– Allergic reactions, parasite infestations, some Timor’s
• Fibroblasts / Myofibroblasts:
– Recruited by macrophages; make collageb
What are giant cells
• Multinucleate cells made by fusion of macrophages • Frustrated phagocytosis • Several types recognised – Langhans -> tuberculosis – Foreign Body Type – Touton -> Fat necrosis
Describe Langhans type giant cell in tuberculosis
Pale foamy cytoplasm
Nuclei around the edge
See slide
Describe foreign body type giant cells
See slide
Describe Touton giant cells
See slide Cell Fatty tissue = avascular Let of fatty material o get rid of Clump togteher to make these Giant cells
How do cell types vary in different conditions in chronic inflammation
• Morphology of most chronic inflammatory reactions is non-specific, BUT proportions of each cell type may vary in different conditions.
• For example:
– Rheumatoid arthritis: Mainly plasma cells.
– Chronic gastritis: Mainly lymphocytes.
– Leishmaniasis (a protozoal infection): Mainly macrophages.
– Giant cell type may be a help to diagnosis.
What are the effects of chronic inflammation?
• Fibrosis e.g. gall bladder (chronic cholecystitis), chronic peptic ulcers, cirrhosis thyrotoxicosis • Impaired function e.g. chronic inflammatory bowel disease – Rarely increased function e.g. mucus secretion, • Atrophy (reduction in size) – gastric mucosa, adrenal glands • Stimulation of immune response – Macrophage - lymphocyte interactions
