Inflammation and healing Flashcards
What is acute inflammation?
Initial and often transient series of tissue reactions to injury
What is chronic inflammation?
subsequent and prolonged tissue reactions following the initial response to injury
What is hypersensitivity?
Inappropriate and excessive immune reaction that damages tissue (altered immune response)
What is a granuloma?
Aggregate of epithelioid histiocytes
What is granulation tissue?
component of healing and repair by 2nd intention
What is a sinus tract?
An abnormal connection between an abscess and mucosal surface
What is a fistula?
An abnormal connection between skin and mucosal surface (or 2 mucosal surfaces)
What is cholecystitis?
Inflammation of the gall bladder
What are the macroscopic appearances of acute inflammation?
Rubor, dolor, calor, tumor (and loss of function)
What are the 4 outcomes of acute inflammation?
Resolution, organisation (granulation –> scar), suppuration, progression to chronic inflammation
What is organisation?
Capillary + fibroblast in growth –> altering the tissue (it is an outcome of acute inflammation)
How is acute inflammation beneficial?
bordering of an abscess in the brain, prevents the spread of infection
Give 5 causes of acute inflammation
tissue necrosis, chemical agents, bacterial toxins, microbial infections, physical agents (Trauma, UV…), Hypersensitivity reactions
What type of fluid is found in acute inflammation?
exudate (protein rich)
What causes increased vascular permeability?
direct vessel trauma, chemical mediators (C3a + C5a, NO, bradykinin, histamine…)
Describe the normal flow of neutrophils
Axial flow
How is the cellular exudate formed?
Chemoattraction causes neutrophils to marginate (flow along vessel wall), adhesion and emigration –> chemotaxis occurs after this
What do neutrophils contain to kill pathogens in a phagosome?
ROS: H2O2, OH, O2…
What are the two initial chemical mediators involved in acute inflammation?
Histamine and thrombin
what 4 enzyme cascades are involved in acute inflammation?
coagulation system, kinin system, fibrinolytic system, complement system
Does chronic inflammation usually result from acute inflammation?
No - it is a primary event
What can chronic inflammation lead to?
Amyloidosis
Give 3 causes of chronic inflammations
Resistance of infective material to phagocytosis + intracellular killing (TB, leprosy), primary granulomatous disease (Crohn’s, sarcoidosis…), UC, autoimmune diseases (RA, pernicious anaemia, hashimoto’s thyroiditis), asbestosis/coal/silica, progression from acute inflammation, transplant rejection (Chronic rejection)
What cells are found in chronic inflammation
Macrophages, lymphocytes, plasma cells, multinucleate giant cells….
Give 4 examples of macrophages
kupffer cells, alveolar macrophages, osteoclasts, microglial cell
What type of giant cell is seen in TB?
Langhan’s giant cell
Give 3 types of giant cells
Langhan’s, Foreign body and Touton giant cells
Is there caseation in sarcoidosis?
No - non-caseating granulomatous inflammation
give 5 diseases with granulomatous inflammation
TB, leprosy, sarcoidosis, Crohn’s, wegener’s granulomatosis, giant cell arteritis
What is the difference between resolution and repair?
In resolution the initiating factor is removed and tissue is undamaged (able to regenerate)
give an example of resolution?
Liver regeneration, lobar pneumonia
Why does pneumonia resolve?
Pneumocytes can regenerate
What are the 3 types of healing in skin?
Abrasian, 1st intention and 2nd intention
give examples of cells that can regenerate
hepatocytes, pneumocytes, blood cells, gut epithelium, skin epithelium, osteocytes
give examples of cells that don’t regenerate
Neurones, myocardial cells
What is repair?
Replacement of damaged tissue by fibrous tissue (collagen produced by fibroblasts)
What is a “scab” composed of?
Layers of fibrin
What is left intact in an abrasian?
Hair follicle and sweat gland
Describe the processes of 1st intention healing
Incised wound –> weak fibrin joint/bridge + coagulated blood –> capillares proliferate, fibroblasts produce collagen, epidermal growth
Explain the process of 2nd intention healing
Tissue has been removed –> formation of granulation tissue –> organisation –> epithelial regeneration
What composes granulation tissue?
Myofibroblasts + capillary loops (collagen deposited)
What do myofibroblasts do?
contract to pull the wound together
How do capillary loops form?
Angiogenesis (VEGF)
What are the complications of scarring?
Deformity, reduced range of movement/function, bowel stenosis and obstruction…
