Chronic Inflammation 2 Flashcards
What is granulomatous inflammation always characterised by?
Granuloma’s (granulomata) in tissues and organs
How is Granulomatous inflammation stimulated?
Indigestible antigen, body cannot get rid of it
How are granulomas formed?
aggregates of epithelioid macrophages in tissue
(Aggregates = collection of particles or cells)
What is epitheliod?
Looks like epithelial, refers to epithelial cells
What might granulomas surround?
Giant cells, dead material
What might granulomas be surrounded by?
lymphocytes
What do granulomas contain?
neutrophils, eosinophils
Granulomas are formed as a result of?
Response to indigestible antigen
Many are type 4 hypersensitivity reactions
What do giant cells consist of?
Mass formed by union of distinct cells (usually macrophages)
Describe the structure of a giant cell?
large cytoplasm; multiple nuclei
- several types
Why is the giant cell often associated with pyogenic granulation tissue
Foreign body type
acutely inflamed
neutrophils, pus
organisation
Name some Infectious granulomatous diseases
Tuberculosis (Mycobacterium tuberculosis)
Leprosy (Mycobacterium leprae)
Syphilis
Give examples of Non-infective granulomas
Rheumatoid disease - tissue specific auto-immune disease
Sarcoidosis
Crohn’s disease – chronic inflammatory bowel disease
What is Sarcoidosis?
Granuloma formation in organs of body
What are the common processes in chronic inflammation?
Acute inflammation
Granulation tissue formation
Local angiogenesis - new vessels grow
Fibrosis and scar formation
What is surgical wound healing?
Healing by primary intention
What are the goals of surgical wound healing?
Minimal gap
Small amount of granulation tissue
Small linear scar
What is healing of larger defects?
Healing by secondary intention
Describe the granulation tissue growth in larger defects
Lots of growth
Contraction and scarring
What is the sequence of events in wound healing?
- injury, blood clot, acute inflammation, fibrin
- many growth factors/cytokines involved
- granulation tissue growth
- angiogenesis
- phagocytosis of fibrin
- myofibroblasts lay down collagen
- contraction of scar
- re-epithelialisation
What conditions favour wound healing?
-Cleanliness
-Apposition of edges
-no haematoma (bleeding outside vessels)
-Sound nutrition
-Metabolic stability and normality
-Normal inflammatory and coagulation mechanisms
-Local mediators
What conditions result in impaired wound healing?
-Dirty, gaping wound, large haematoma
-Poorly nourished, lack of vitamins C, A
-Abnormal CHO(carbs) metabolism, diabetes, corticosteroid therapy
-Inhibition of angiogenesis
What is the sequence of events in fracture healing?
-Trauma, fracture, haematoma
-Dead bone and soft tissue
-Acute inflammation, organisation, granulation tissue, macrophages remove debris
-Granulation tissue contains osteoblasts and fibroblasts
What are the stages of callus formation?
-Osteoblasts lay down woven bone
-Nodules of cartilage present
-Followed by bone remodelling:
.osteoclasts remove dead bone
.progressive replacement of woven bone by
lamellar bone
.reformation of cortical and trabecular bone
What stimulates proliferation of vessels?
VEGF, released by hypoxic cells, stimulates proliferation
(VEGF = Vascular endothelial growth factor)
What aids the process of angiogenesis?
Enzyme secretion
What is the benefit of angiogenesis?
Allows blood supply to enter damaged tissue
What is the effect of angiogenesis on thrombus
Grows vessels through thrombus, limits its propagation
What is the effect of angiogenesis in malignant tumours
allows tumour growth
potential for therapeutic control
