Chronic inflammation Flashcards
Define chronic inflammation
Inflammation in which the cell population is especially high in lymphocytes, antibodies and macrophages
features tissue/ organ necrosis and loss of function
How may chronic inflammation arise
Primary pathology
Follow on from acute inflammation
List the cell types involved in chronic inflammation
B-cell mechanism T-cell mechanism NK cells Macrophages Fibroblasts
Describe the mechanism of B cells in chronic inflammation
Differentiate into plasma cells (antibodies)
Facilitate immune responce
Act with macrophages
Create immulogical memory
Describe the mechanism of T cells in chronic inflammation
Produce cytokines; -attract and hold macrophages -activate immune cells -alter capillary permeability Produce interferons (signalling proteins); -antiviral effects -attract and stimulate cells Kill cell and destroy antigen
Describe the mechanism of NK cells in chronic inflammation
Destroy antigens and cells
Describe the mechanism of macrophages in chronic inflammation
Remove debris
Motile phagocyte in blood
Describe the mechanism of fibroblasts in chronic inflammation
Motile cells
Make and assemble structural proteins (collagen)
Define granulomas
A group of epitheliod macrophages in tissue
May contain giant cells (large macrophages) , surround dead material or be surrounded by lymphocytes
What do granulomas contain
neutrophils and eosinphils
What are granulomas a response to
an indigestible antigen
Give examples of global scale granulomas inflammation and their casues
TB - mycobacterium tuberculosis
Leprosy - mycobacterium leprae
Syphilis - treponema pallidum
Describe theprocess of granulation in organisation
granulation tissue flows into damaged tissue
capillaries grow into inflammatory mass
increased flow of plasma proteins and macrophages
fibroblasts lay down collagen to repair damages tissue (replace exudate)
What do fibroblasts and collagen do to damaged tissue
Patch tissue defects and replace dead tissue to pull it together
Produces scar - small blemish on the skin - to heal
List the sequence of events in wound healing
Injury > blood clot > acute inflammation > fibrin meshwork Increased growth factors and cytokines Granulation tissue growth Phagocytosis of fibrin Fibroblasts lay down collagen Contraction of scar Re-epithelialisation
What is different about granulation tissue in bones?
It contains osteoblasts as well as fibroblasts
Describe the process of callus formation
Osteoblasts lay down woven bone with cartilage nodules
Describe the process of bone remodelling
Osteoclasts remove dead bone
Replacement of woven bone by lamellar bone
Reformation of cortical + spongy bone (by osteoblasts)
List the factors involved in promoting wound healing
Cleanliness Apposition of edges (no hematoma) Good nutrition Metabolic normality Normal inflammatory and coagulation mechanism
List the factors involved in impairing wound healing
Dirty, gaping wound Large hematoma Poorly nourished (lack of vit A/C) Abnormal metabolisms Inhibition of angiogenesis
Define hematoma
an abnormal collection of blood outside of a blood vessel
It occurs because the wall of the vessel has been damaged and blood has leaked into tissues where it does not belong
Define the role of angiogenesis in healing and repair
New vessels form capillary buds, enabling blood supply to enter damaged tissue
What stimulates the proliferation of new blood vessels
VEGF released by hypoxic cells and enzymes
What do cytokines do as part of the T cell mechanism
- attract and hold macrophages
- activate immune cells
- alter capillary permeability
