Inflammation + repair Flashcards
What are the 5 main signs of acute inflammation?
Redness: Increased blood flow and congested vessels
Heat : Increased blood flow + vasodilation
Swelling: increased vascular permeability means more exudate leaves the vessels
Pain: Release of prostaglandins, cytokines, chemokines
Loss of function: Loss of functional cells and connective tissue
What are the 3 characteistic features of acute inflammation?
Vasodilation: Increases blood flow to tissues
Histamine induces opening of capillary beds
- Increases vessel permeability so more proteins and fluids can leave the cell/exudate
- Migration of leukocytes to the site of injury
How do leukocytes migrate to the site of injury?
Margination + rolling Rolling adhesion Diapedesis Leukocytes escape from blood vessels ( extravasation) to migrate to the site of injury Leukocytes move via chemotaxis
What are the 3 main functions of neutrophils?
Phagocytosis
Netosis
Granzyme + apoptosis
How do inflammatory mediators cause a systemic response?
Inflammatory mediators act on the hypothalamus and activate the sympathetic nervous system
Activates liver to produce acute phase proteins
Activates bone marrow to produce leukocytes
What cell types dominate in acute inflammation?
Neutrophils ( multi lobed nucleus)
Then replaced by monocytes ( bean shaped nucleus)
What are the 3 types of acute inflammation?
Fibrinous: Vascular leaks and pro coagulant stimuli lead to the production of fibrin depositions.
Pyogenic : Due to pus producing bacteria e.g staphylococcus aureus
Ulcerative/supurlative:
What are the 3 outcomes of acute inflammation?
Resolution, cause of inflammation has been eradicated
Healing by fibrosis, loss of some tissue function and scar formation
Progression to chronic inflammation: Cause of inflammation not removed
What can be the causes of chronic inflammation?
Organism difficult to eradicate
Autoimmune disease/hypersensitivity
Unresolved acute inflammation
Immune deficiencies
What are the main features of chronic inflammation?
Loss of normal adenexal structures Healing by fibrosis/scarring Loss of CT matrix Angiogenesis and fibrosis Tissue infiltration with inflammatory cells
What is granulomatous inflammation?
Type of chronic inflammation characterised by aggregates of macrophages
It is a response to an organism that is difficult to eradicate
What are the 3 types of granulomatous inflammation?
Which types have a T cell response?
Foreign body: Response to an inert foreign material e.g sutures. No T cell response
Immune: Response to agents that induce a T cell response
Caseating: Associated with specific infections such as mycobacterium tuberculosis. Pink amorphic centre + loss of normal tissue structure. Hypoxic
What is the role of growth factors in tissue repair?
Drive cells capable of regeneration to proliferate. They must have an intact ECM
Growth factors are produced by macrophages, stromal cells and epithelial cells
They bind to the ECM and induce protein production so the cell can pass to the next stage of the cell cycle
Cells use Integrins to adhere to the ECM which stimulates proliferation
When does healing by scarring/fibrosis occur?
Extensive damage
Unable to regenerate
No ECM
Describe the process of healing by scarring/fibrosis
Fibroblasts migrate to the site of injury and proliferate along with epithelial cells
Granulation tissue forms
Angiogenesis
Deposition of connective tissue
Cytokines and growth factors stimulate migration and proliferation of fibroblasts and deposition of the ECM
Vascular regression as the scar matures
Myofibroblasts contribute to scar contraction
CT is remodelled and modified by MMPS
