Acute Inflammation Flashcards
what is acute inflammation?
quickly developing response of living tissue to infection/damage, initiation for innate immunity
what are the three main processes involved in acute inflammation?
vascular dilation, increased vascular permeability, neutrophil activation and migration
how long does acute inflammation last for?
few hours to days
what are the four main causes of acute inflammation?
microbial infection, physical agents, irritant and corrosive chemicals, tissue necrosis
what does microbial inflammation result from?
microbial recognition
what are the physical agents of acute inflammation?
physical trauma, UV radiation, heat, cold
what are the irritant and corrosive chemicals that cause acute inflammation?
acids, alkali, oxidising agents, microbial virulence factors
what causes tissue necrosis?
lack of oxygen or nutrients, inadequate blood flow
what are the cardinal signs of inflammation?
redness, heat, swelling, pain and loss of function
how does an inflamed area redden?
dilation of small blood vessels
how does an inflamed area have heat?
increased blood flow
how does swelling occur in acute inflammation
accumulation of fluid in extra vascular space (oedema)
how does pain occur in inflammation
stretching/distortion of tissues due to oedema, chemical mediators induce pain
give an acute inflammation
gingivitis
what are the 4(5) steps of inflammation?
initiation, progression, amplification, resolution, no resolution?
what is the initiation stage of gingivitis?
microbes in dental plaque recognised by gingival epithelial cells via pattern recognition receptors
what is the progression stage of gingivitis
containment of microbes by innate immune cells and antimicrobial compounds (AMPs and secretory IgA)
what is the amplification stage of gingivitis
recruitment and activation of innate immune cells via chemokine/cytokine activity and vascular dilation
what is the resolution stage of gingivitis?
healing and repair
what happens if there is no resolution in gingivitis
periodontitis
what are the steps of the amplification stage of inflammation?
bacteria trigger macrophages to release cytokines and chemokines - vasodilation and increased vascular permeability cause redness, heat and swelling - inflammatory cells migrate into tissue, releasing inflammatory mediators that cause pain
what are the vascular responses to inflammation?
small blood vessels adjacent to site of damage become dilated, endothelial cells swell and retract, exudation, endothelial cells activated to promote immune cells passage to damaged tissues
what does retraction of endothelial cells result in?
migration of neutrophils and monocytes/macrophages to damaged tissues
what does exudation mean?
the vessels become leaky and allow passage of water, salts and some proteins
what is oedema?
defined as an excess of watery fluid collecting in the cavities or tissues of the body, increased blood and lymph flow
what does inflammatory exudate provide to tissues?
fluids and salts, glucose and oxygen, complement proteins and antibodies, fibrin
what does increased lymph flow allow?
increased influx of inflammatory infiltrate
what are the different types of mediators
chemical or protein
what are the main types of chemical mediators?
HISTAMINE, BRADYKININ, PROSTAGLANDINS, leukotrienes and serotonin
what are the protein mediators?
cytokines and chemokines
what is histamine?
breakdown product of histidine
where is histamine stored?
in granules of immune cells such as mast cells
what does degranulation do?
release histamine
what is the role of histamine?
a neurotransmitter causing itching
what does histamine cause?
vascular dilation
what are prostaglandins produced by?
macrophages and neutrophils (with leukotreines)
what is a prostaglandin
the product of fatty acid metabolism
what is the most abundant prostaglandin?
prostaglandin E2 (PGE2)
what do prostaglandins cause?
vascular dilation
what are the roles of prostaglandins in acute inflammation
regulate cytokine production, regulate cell recruitment, act on nerve fibres causing pain, involved in tissue remodelling
what are prostagandins released from cells in response to?
numerous stimuli
what are prostaglandins regulated by?
cyclo-oxygenase II (COX II)
how is cyclo-oxygenase II (COX II) activated?
through the stimulation of cells by TLR activation
what type of mediators regulate blood vessel changes?
protein and chemical mediators (histamine and prostaglandins)
what do inflammation processes function to do?
provide tissue with necessary tools to eliminate inciting cause and repair any damage
what type of cascade are all the four systems of plasma factors?
proteolytic cascades, stepwise activation involving formation of enzyme complexes and protein cleavage
what are the four enzymatic cascades of plasma factors?
complement, the kinin system, the fibrinolytic system, coagulation
what is the common activator of the kinin, fibrinolytic and coagulation systems?
Hageman factor (coagulation factor 12)
how are the four plasma systems interconnected
all activated by the same factor, kinin system produce kinins and fibrinolytic systems produce plasmin which both activate the complement systems, plasmin from fibrinolytic system degrades fibrin produced by the coagulation system
what is the initiating factor of the classical pathway of complement?
antibody attached to microbe
what are the 3 pathways of complement?
classical, alternative, mannose binding lectin pathway
what is the initiating factor of the alternative pathway of complement?
microbial cell wall
what is the initiating factor of the mannose binding lectin pathway of complement?
carbohydrates on pathogen surface
what generates kallikrein?
the hageman factor
how do neutrophils contribute to the kinin-kallikrein system?
release kallikreins
what does kallikrein do?
converts kininogens to kinins (e.g. bradykinin)
what are the functions of kinins e.g. bradykinin
stimulate complement system, promote localised vasodilation and increased capillary permeability, activate pain receptors, act as chemotaxins
what are the three pathways of the coagulation system?
intrinsic, extrinsic and common
what is the intrinsic pathway of the coagulation system?
activated when blood comes into contact with sub-endothelial connective tissues
what is the extrinsic pathway of the coagulation system?
damaged blood vessel means Human Factor 7 leaves vessel and encounters tissue factor in surrounding tissue
what is the common pathway of the coagulation system?
production of thrombin which in turn produces fibrin (clot formation)
what does the kinin system produce?
kinins
what does the coagulation produce?
fibrin
what does the fibrinolytic system produce?
plasmin
what is the main constituent of clotting?
fibrin
what does the fibrinolytic system do?
involved in the breakdown of clots, prevents clotting, activates complement and indirect role as fibrin degradation products promote vascular permeability
what do fibrin degradation products do?
promote vascular permeability
what is haemostasis?
the balance between the coagulation and fibrinolytic system
what does haemostasis essentially mean?
to stop the flow of blood
name some congenital coagulation disorders
von willebrand disease, haemophilia A and B
what drugs cause acquired coagulation disorders?
warfarin and heparin
summarise complement
three pathways - leads to membrane attack complex formation and anaphylatoxin production
summarise the kinin system
plasma proteins/enzymes that lead to production of bradykinins
summarise coagulation
three pathways - formation of a stable blood clot (fibrin)
summarise the fibrinolytic system
plasmin prevents excessive clotting of blood by degrading fibrin
what is disease resolution dependent on?
tissue involved, amount of tissue destruction, nature of the harmful agent
what is abscess formation (suppuration) an outcome of?
acute inflammation
what is suppuration?
the formation of pus usually arising from an infection with pyogenic bacteria
what is pus
bacteria with dead and dying neutrophils
what surrounds pus once it accumulates?
a pyogenic membrane
what are the 3 types of dental abscesses?
gingival, periodontal and periapical
what is a gingival abscess?
an abscess formed due to infection or trauma to the surface of gum tissue
what is a periodontal abscess?
abscess formed due to infection that has moved deeper into the gum areas. this is sometimes called a gum boil
what is a periapical abscess?
an abscess of a tooth due to infection of the pulp
what does the resolution of acute inflammation require?
minimal cell death and tissue damage, occurrence in tissues with regenerative capacity, rapid elimination of causative agent, rapid removal of fluid and debris by vascular/lymphatic drainage
what is the most common outcome of acute inflammation?
resolution
