Inflammation 2 Flashcards
What are the events of acute inflammation
Stimulus for inflammation
Vascular changes
Cellular events
Termination of acute inflammatory response
What can be the cause of acute inflammation
Infectious agents
Trauma
Necrotic tissue
Immune reactions
What are the inflammatory mediators of acute inflammation
Vasoactive amines Plasma proteases: complement Lipid mediators Platelet activating factor Cytokines Chemokines Nitric Oxide
What are the vascular changes in acute inflammation
Increased vascular flow (hyperemia) and blood vessels
Increased vascular permeability (capillaries and post-capillaries)
What are the cellular events of acute inflmmation
Extravasation- deliver of WBC to site of injury
Migration- cytokines
Rolling- selectin/integrin
Activation and Adhesion- integrin and chemokines
Transmigration - P-CAM
The process where WBC emigrate in tissues towards the site of injury
Chemotaxis
What are the 3 processes involved in phagocytosis
Recognition and attachment of particle
Engulfment with subsequent formation of phagocytic vacuole
Killing or degradation on ingested material
How is the acute inflammatory response terminated
Degrade inflammatory mediators
Stop signals
->pro-inflammatory leukotrienes to anti-inflammatory lipoxins from arachidonic acid
-> anti-inflammatory cytokines from macrophages
-> neural impulse inhibits TNF production in macrophages
What are the four outcomes of acute inflammation
Complete resolution
Healing by scarring
Abscess formation
Chronic inflammation
What is involved in inflammatory resolution
Neutralization of chemical mediators
Return to normal vascular permeability
Stop lymphocytic infiltration and removal of edema
Healing by scarring often occurs in what type of tissue
Tissues that do not have the ability to regenerate
How can chronic inflammation arise?
Following acute inflammation - persistent stimulus or interference in normal process
Repeated bouts of acute inflammation
Low grade response
Persistent infection by intracellular micro organisms which are low toxicity or prolonged exposure to non-degradable substances usually result in what kind of inflammation
Chronic
A small organized collection of modified macrophages (epithelioid cells) surrounded by a rim of lymphocytes
Granuloma
Granulomatous inflammation = Chronic!
What are some causes of granulomatous inflammation
Insert particles. Eg silica/asbestos Lipid resistant to metabolism Bacterial resistant to lysosomal degradation Systemic fungal agents Foreign bodies
What are the cells involved in granulomatous inflmmation
Epithelioid cells
Multinucleated giant cells
Lymphocytes
A large, pale-staining, eosinophilic macrophage with a ovoid nucleus, rich with ER, golgi, and vesicles
Epithelioid cells
Fusion of macrophages induced by cytokines causes formation of ______________________
Multinucleated giant cells
Nuclei are sometimes arranged around the periphery
What are the roles of T lymphocytes
To produce lymphokine and interferons
To attract ad activate macrophages
To induce formation of multinucleated giant cells
What are the two patterns of chronic inflammation?
Diffuse thickening of affected tissue (eg Johnes disease)
Solid, firm, nodular lesions ->may compress adjacent tissue
The term used when there are significant numbers of neutrophils present in the center of a granulomatous reaction
Pyogranulomatous
Organized accumulation of machrophage so and epithelioid cells, often rimmed by lymphocytes
Simple granuloma
May be diffuse or local
Granuloma with a central area of necrosis
Complex granuloma
-necrosis may lead to calcification/mineralization
What is the sequelae of chronic inflammation ?
Persistence of stimuli-> progression of inflammatory rxn -> continuation of disease
Process by which lost or necrotic cells are replaced by vital cells
Repair
What are the two types of repair
Paraenchymal regeneration
Fibrosis
Injured tissue replaced by identical types of tissue, leaves no residual trace of pervious injury
Parenchymal regeneration
Parenchymal regeneration can only occur if:
Tissue can regenerate
framework of the tissue is maintained
Replacement of tissue by fibrous CT
Fibrosis
Fibrosis results in increased amount of ________ in tissue
Collagen
What are labile cells
AKA continuously dividing cells
Follow the cell cycle from one mitosis to the next; proliferate throughout life
Tissues composed of these cells regenerate after injury
What are examples of labile cells?
Surface epithelial
Lining mucosa
Columnar epithelium of GI tract, uterus, Fallopian tubes
Transitional epithelium - urinary tract
Spleen, lymphoid, and hematopoietic tissue
What are stable cells
Aka quiescent cells
Low level of replication
Can undergo rapid division in response to stimuli
What are examples of stable cells
Epithelium of liver, kidney, lung, pancreas
Smooth muscle
Fibroblast
Vascular endothelium
What are permanent cells
Aka non-dividing cellls
Cannot undergo mitotic division after postnatal life
What are examples of permanent cells?
Neurons
Cardiac muscle cells
What are the 4 components of fibrosis ?
Migrate and proliferation of fibroblasts
Deposit ECM
Form new blood vessel
Maturation and organization of the scar (remodeling)
What factors favor fibrosis over regeneration
Severe/prolonged tissue injury
Loss of framework (basement membranes)
Large amount of exudate -> body able to eliminate
Lack of renewable cell populations
What are the consequences of fibrosis
Loss of functional parenchymal tissue
Alteration of physical properties of tissue
-> skin scar prone to tearing
-> pulmonary -> decreased compliance and vital capacity
When does granulation tissue form?
3-5 days after injury
What tissue is pink, soft, and granular on the surface of a wound.
Granulation tissue
Granulation tissue is composed of what 4 tissue zones?
Surface (young) -> deep tissue (old)
Zone of necrotic debris
Zone of macrophage and angiogenesis
Zone of proliferating capillaries and fibroblast
Zone of fibrous CT
What is the sequence of events of granulation tissue maturation
Bed of granulation tissue matures
Deposits of collagen and ground substance
Granulation bed contracts
Specialization of some fibroblasts into contractile cells
What is the difference between and granuloma and granulation tissue
Granuloma = chronic inflammation
Granulation tissue= repair process with large amount of fibrous CT and neovascularization
Process including CT replacement and regeneration by which restoration of tissue continuity achieved
Wound healing
Healing by first intention vs second intention
First intention: little exudate and tissue edges are close together (little scar)
Second intention : edges of wounds are widely separated (mas scar)
What is the general process of skin healing ?
Blood clot
Epithelial continuity is restored (24-48hrs)
Epithelial cells lose contact with BM and other cells ->migrate to advancing edge ->mitosis to gradually cover epidermal defect
Inflammatory reaction -> neutrophil infiltration followe by macrophage
Neovascularization
Fibroblast proliferation and laying down of collagen
Devasculrization
Regression of inflammatory cells and fibroblasts
Scar
Remaining hepatocytes regenerate and some ECM framework is destroyed resulting in formation of irregular hepatocyte nodes separated by fibrous CT scars
Massive hepatic necrosis
_______ of the kidney has maximal regenerative capacity while the _____________ has minimal regenerative capacity
Renal cortical tubules; renal medullary tubules
____________ of the kidney has no regenerative capacity
Glomeruli
How does the kindey repair by regeneration
No rupture of cortical tubule BM
Surviving cells flatten, appear squamoid and migrate to necrotic area
