Acute Inflammation Flashcards
What are the 4 general causes of acute inflammatory responses?
Microbial infections
Hypersensitivity
Physical agents
Chemical agents
What are the 5 symptoms to recognise acute inflammation?
Red- rubor
Hot- calor
Swollen- tumor
Painful/tender- dolor
Loss of function
What is redness caused by?
Dilation of blood vessels
What is swelling caused by?
Mainly due to oedema
What are the two phases of acute inflammation?
Initial and
What are the two phases of the initial reaction?
Vascular phase
Exudative phase
What happens in the vascular phase?
Dilation and increased permeability
What happens in the exudative phase?
Fluid and cells escape from permeable venules
What is the characteristic cell in acute inflammation?
Neutrophil polymorph
What happens to capillaries in acute inflammation?
Precapillary sphincter opens to allow blood flow into capillary beds
What happens to the plasma protein in acute inflammation?
There us a net flow out of the arterial and venous system
What is the protein content in the exudate phase?
Higher than normal
What plasma proteins are released in the exudate phase?
Immunoglobins
Fibrinogen
Fibrin
Why are immunoglobins important?
Important for destruction of invading organisms
What happens to fibrinogen in exudate phase?
It is converted to fibrin
What happens to the fluid developed in the exudate phase?
It is continuously removed via lymphatics
What is the transudate state ?
Normal state
What is the exudate phase in relation to the transudate?
Net flow out
Increased vascular permeability
High protein content
What does histamine and bradykinin do?
Increase vascular permeability
How is increased vascular permeability brought about?
Stimulation of endothelial cell and changes in the cytoskeleton which cause transient, intercellular gaps
What happens to the lymphatic system in inflammation?
The lymphatics dilate and drain fluid from the exudate
The antigens are then carried to the lymph nodes and these are recognised by lymphocytes
What causes swollen lymph nodes in response to an infection?
The increase of B cells within the B cell area in reaction to the higher number of antigens
Where does fluid enter and leave the lymph node?
Afferent lymphatic
Efferent lymphatic
What is lymphangitis?
Inflammation of the lymphatic vessels
What is lymphadenitis?
Inflammation of the lymph nodes
What is the function of neutrophils?
Kill organisms
Degrade necrotic tissue
Ingest offending agents
Produce chemical mediators
Produce toxic oxygen radicals
Produce tissue damaging enzymes
Describe diapedesis in acute inflammation
The neutrophils adhere to the vessel wall (pavementing) and squeeze through the endothelial cells into the adventitia
What do selectins control?
The adherence of neutrophils to the post capillary venule wall
What do integrins and immunoglobin I like cells do?
Activation of transmigration
What is neutrophil chemotaxis?
When neutrophils move along a concentration gradient of chemotactic compounds which lead to the antigen
How does the body react to chemical injury that cause acute inflammation?
By releasing chemical mediators
What are the effects of chemical mediators?
Vasodilation
Emigration of neutrophils
Chemotaxis
Increased vascular permeability
Itching and pain
What are the four enzymatic cascade systems contained in plasma?
Complement cascade
The kinins
The coagulation factors
Fibrinolytic system
How are most micro-organisms recognised?
Coated in opsonins
These opsonins then can bind to specific receptors of leucocytes and greatly enhance phagocytosis
What are some major opsonins?
Fc fragment of IgG
C3b
Collectins
What are some classic signs of acute inflammation?
Serous
Catarrhal
Fibrinous
Haemorrhagic
Suppurative
Membranous
Pseudomembranous
What is serous?
Protein rich fluid exudate
What is catarrhal?
Mucus hypersecretion
What is fibrinous?
Exudate contains plentiful fibrin
What is haemorrhagic?
Severe vascular injury
What is suppurative?
Production of pus
What is membranous?
Epithelium coated by fibrin
What is pseudomembranous?
Superficial mucosal slough
What is pus made from?
Neutrophils, bacteria and cellular debris
What is an abscess?
Collection of pus surrounded by a membrane of sprouting capillaries, neutrophils and occasional fibroblasts
What is an ulcer?
Local defect or excavation, of the surface of an organ or tissue that is produced by sloughing of inflammatory necrotic tissue
What is some benefits of acute inflammation?
Dilution of toxins
Entry of antibodies
Fibrin formation- impedes movement of microorganisms
Transport of drugs
Delivery of nutrients and oxygen
Stimulation of the immune response
What is NETosis?
When a neutrophil meets its target, it explodes releasing all its DNA which binds to the pathogens
What are some harmful effects of acute inflammation?
Digestion of normal tissues
Swelling
Inappropriate inflammatory response
What is type I hypersensitivity?
Allergic reaction
What is an allergic reaction caused by?
Allergen recognised by immune system
Immune system releasing IgE which then bind to mast cells and cause the release of inflammatory mediators
How is fever generated in acute inflammation?
Infectious agents, immunological and toxic reactions cause release of endogenous pyrogens
These then enter the preoptic nucleus hypothalamus which increases the temperature
Examples of endogenous pyrogens
Interleukin 1
Interleukin 6
Tumour Necrosis Factor
What are some haematological changes seen in acute inflammation?
Increased erythrocyte sedimentation rate
Anaemia
Leucocytosis
What process from acute inflammation leads to suppuration?
Excessive exudate
What process from acute inflammation leads to repair and organisation?
Excessive necrosis
What process from acute inflammation leads to chronic inflammation?
Persistent chemical agent
