acute inflammation Flashcards
what is acute inflammation?
response of living tissue to infection/ damage
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?
develops quickly and lasts only a few hours to days
what are the four main causes of acute inflammation?
- microbial infection
- physical agents
- irritant and corrosive chemicals
- tissue necrosis (tissue death)
what are examples of physical agents which can cause acute inflammation?
Physical trauma
Ultraviolet or other ionizing radiation
Heat (burns)
Cold (frostbite)
what are examples of physical agents which can cause acute inflammation?
Physical trauma
Ultraviolet or other ionizing radiation
Heat (burns)
Cold (frostbite)
what are examples of irritants and corrosive chemicals which can cause acute inflammation?
- acid, alkali and oxidising agents
- microbial virulence factors
what is tissue necrosis?
death of tissue due to:
- lack of O2 or nutrients
- inadequate blood flow (infarction)
what are the consequences of acute inflammation?
- redness
- heat
- swelling
- pain
- loss of function
why does redness arise in acute inflammation?
dilation of small blood vessels
why does heat arise in acute inflammation?
increased blood flow (hyperaemia)
why does swelling arise in acute inflammation?
accumulation of fluid in extra vascular space (oedema)
why does pain arise in acute inflammation?
Stretching/distortion of tissues due to oedema.
Chemical mediators induce pain
what is the best example of acute inflammation?
gingivitis
describe the initiation, progression, amplification and resolution of gingivitis
what is amplification?
recruitment and activation of innate immune cels via chemokine/cytokine activity and vascular dilation
what are chemokines and cytokines produced by?
macrophages and epithelial cells
describe vascular response
Small blood vessels adjacent to site of damage become dilated
Endothelial cells swell and retract
Exudation – the vessels become ‘leaky’ and allow passage of water, salts and some proteins
Endothelial cells activated to promote immune cells passage to damaged tissues
what is oedema?
an excess of watery fluid collecting in the cavities or tissues of the body (swelling)
what does inflammatory exudate provide to the tissue?
Fluids and salts
Glucose and oxygen
Complement proteins and antibodies
Fibrin (long insoluble filamentous protein)
what are the two sub groups within mediators?
chemical and protein
give examples of chemical mediators
histamine
bradykinin
prostaglandins
where is histamine stored?
granules of immune cells such as mast cells
what process released hsitamine?
degranulation
what are the functions of histamine?
Role as a neurotransmitter – itching
Causes vascular dilation
what is prostaglandin produces by?
macrophages and neutrophils
what is the most abundant type of prostaglandins?
prostaglandins E2
what are the functions of prostaglandins?
- vascular dilation
- Regulate cytokine production
- Regulate cell recruitment
- Act on nerve fibres – pain
- Involved in tissue remodeling
when are prostaglandins released?
in response to numerous stimuli
what regulates prostaglandins?
the enzyme cyclo-oxygenase II
what are the four enzymatic cascades involved in plasma factors?
Complement
The kinin system
Coagulation
Fibrinolytic system
what can activate all the enzymatic cascades in plasma factors?
coagulation factor XII
what is kallikrein generated by in the kinin system?
hageman factor (coagulation factor XII)
what is the function of kallikrein?
converts kininogens to kinins
what are the three pathways of the coagulation system?
- intrinsic
- extrinsic
- common throbin
when is the intrinsic coagulation pathway activated?
when blood comes into contact with sub-endothelial connective tissues (outside blood vessel)
what do all three of the coagulation system pathways lead to?
production of fibrin (blood clot)
what does the fibrinolytic system result in?
the activation of plasmin
(prevents excess clotting in health)
what is haemostasis?
the balance between the coagulation and fibrinolytic system
what does haemostasis mean?
to stop the flow of blood
what are examples of congenital coagulation disorders?
Von Willebrand disease (VWD)
Haemophilia A
Haemophilia B
what are examples of acquired coagulation disorders?
Warfarin
Heparin
what is an outcome of acute inflammation which can lead to chronic inflammation?
abscess formation (suppuration)
what are the three types of dental abscess?
Gingival abscess
Periodontal abscess
Periapical abscess
what is pus?
bacteria with dead and dying neutrophils
how is acute inflammation resolved?
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
how is acute inflammation resolved?
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
