Inflammation Flashcards
What is the purpose of inflammation?
To destroy or control the harmful stimulus, initiate repair and restore function
Give examples of situations in which inflammation occurs pathologically?
Autoimmune disease
Atheroma
Cancer
During inflammation what factors mediate vasodilation?
Histamine from mast cells
Prostaglandins and NO
During inflammation, what factors result in neutrophil activation?
C5
Leukotrienes
B4
Bacterial products
During inflammation, what factors result in endothelial activation?
5-HT Histamine C3 C5 Bradykinin Leukotrienes
What is the result of activation of the endothelium in inflammation?
Increased cell adhesion molecules
Increased leakiness of endothelium
Movement of plasma proteins (immunoglobulins, complement, fibrinogen) into tissues
What cytokines do macrophages produce in an inflammatory reaction?
TNF
IL-1
IL-6
The binding of which type of antibody stimulates degranulation of mast cells?
IgE
Other than the binding of IgE, what can stimulate mast cells to degranulate?
Injury
Complement
What is the role of plasma cells in inflammation?
Antibody production
Rolling adhesion of white cells in the blood is regulated by selecting. What factors up regulate selections?
IL-1
TNF
(FROM MACROPHAGES)
What factors mediate the adhesion of white blood cells to the endothelial walls prior to diapedesis?
Integrins
GPCRs recognise products of short bacterial peptide, complement and prostaglandins in order to induce chemotaxis and production of the respiratory burst. Which leucocytes utilise this type of receptor?
Plasma cells
Macrophages
Receptors for opsonins exist on the surface of WBCs, What is the purpose fo these?
These coat a particle to target for ingestion
What cytokine can activate macrophages?
INF-gamma
What is the purpose of C5a in the complement pathway?
Chemotactic for neutrophils
Increases vascular permeability
Releases histamine from mast cells
What factors in the complement pathway have cytolytic activity?
C5 C6 C7 C8 C9
What factors in the complement pathway opsonise bacteria?
C4b
C2a
C3b
What are the steps involved in phagocytosis?
Opsonisation Engulfment using pseudopodia Formation of phagosomes Fusion with lysosomes containing enzymes to form phagolysosomes Destruction of material Removal from the cell by pinocytosis
What are the clinical signs of inflammation and how are these caused?
Redness, heat and swelling caused by hyperaemia
Pain caused by release of bradykinin and PGE2
Loss of function caused by combination of above signs
How is acute inflammation terminated?
Removal of stimulus Short half life of neutrophils Variation in cytokine stimuli Neural impulses Macrophages activated to perform different functions
How can infection by spread?
Natural barriers
Air borne
Blood borne
Immune factors
What are the benefits of acute inflammation?
Dilutes toxins through oedema Increases entry of antibodies Increases drug transport Fibrin traps micro-organisms Delivers nutrients Stimulates immune response
What are the detrimental effects of acute inflammation?
Digestion of normal tissues
Swelling e.g. epiglottitis
Inappropriate responses e.g. hypersensitivity
How can systemic infection spread?
Through lymph or blood
What factors control the spread of infection?
Virulence of the organisms Host condition (i.e.immunosuprresion) Low protein levels Poor vascular supply Treatment given
What are the four key clinical features of a systemic inflammatory response?
Increased respiratory rate
Increased heart rate
High or low temperature
High or low white cell count
In what cases will there by resolution of acute inflammation?
If there is minimal tissue damage
Occurs in tissue with regenerative capacity
Cause is rapidly removed or destroyed
Good vascular drainage
In what cases will there be healing by fibrosis following acute inflammation?
After substantial tissue damage
If tissue is incapable of regeneration
If there is abundant fibrin exudate
In what cases will acute inflammation persist to chronic inflammation?
Persistence of stimulus
Tissue destruction leading to ongoing inflammation
What is an exudate?
An extracellular fluid with a high protein and cellular content
What is a transudate?
An extracellular fluid with a low protein and cellular content
What is the role of an exudate in inflammation?
Allows delivery of nutrients
Dilution of toxins
Entry of antibodies
Stimulates immune response
Describe a serous exudate
Usually transudate, found in pleural, pericardial, peritoneal spaces
Describe a fibrinous exudate
fluid rich in fibrin, often on serial surface/meninges
Describe a suppurative exudate
Pus forming, an exudate ruch in neutrophil polymorphs
Describe a haemorrhagic exudate
severe vascular injury or depletion of coagulator factors
Describe a membranous exudate
epithelium becomes coated in membrane formed by fibrin, epithelial cells and inflammatory cells
Describe a pseudomembranous (ulceration) exudate
surface exudate on mucosal/exudate sites e.g. c diff colitis
Describe a necrotising exudate
high tissue pressure leading to vascular occlusion and thrombosis
When is inflammation defined as chronic?
Persistent and lacks resolution when the inflamed tissue is unable to overcome the effects of the injurious agent
Persists for weeks, months or years
Characterised by infiltrates of lymphocytes, plasma cells and macrophages
Chronic inflammation will always lead to scarring. T/F?
True - there will always be a degree of scarring
What cells are involved in chronic inflammation?
Macrophages, plasma cells, lymphocytes
What factors determine whether or not chronic inflammation will take place?
Site affected Type of wound Presence of infection Type of organism involved Presence of indigestible material Treatment given Background disease
What is granulomatous inflammation?
A distinctive pattern of chronic inflammation where the predominant cell types involved are activated macrophages with a modified appearance (epithelioid macrophages) and giant cells
Giant cells are formed from fused epithelioid macrophages. T/F?
True
What type of inflammation is classically seen in tuberculosis?
Caseous necrosis
Give examples of infectious agents which can cause granulomatous inflammation?
Tuberculosis
Leprosy
Toxoplasmosis
Give examples of substances/conditions, other than infectious agents which can cause granulomatous inflammation?
Talc or other foreign materials
Sarcoidosis
Chron’s disease
Hodgkin’s lymphoma
What are epithelioid macrophages?
Modified macrophages arranged in small nodules or clusters which have a mainly secretory role
The formation of granulomas is an example of what type of hypersensitivity?
Type 4
What tissues are affected by rheumatoid arthritis?
Skin Blood vessels Heart Lungs Joints Muscle
In rheumatoid arthritis, what WBCs are present in the synovial fluid?
Neutrophils
Which type of WBC are particularly involved in the pathogenesis of atherosclerosis?
Macrophages - these become foam cells in atherosclerosis
In choleric granulomatous disease there is a defect in which enzyme system?
NADPH oxidase system
In which condition is there a defect in the NADPH oxidase system which results in an inability to kill intracellular organisms by respiratory burst?
Chronic granulomatous disease
What type of wound heals by primary intention?
Incised wound
Healing by primary intension is more likely to leave a scar than healing by secondary intention. T/F?
False- the opposite is true
In fracture healing, how long does it take the soft callus to ossify?
4-6 weeks
in fracture healing, for how long does remodelling occur?
Months to years
What are the steps in fracture healing?
Formation of a haematoma
Recruitment of leucocytes to the site and formation of granulation tissue
soft callus formation
remodelling
What are the steps in cutaneous wound healing?
Formation of blood clot, formation of granulation tissue, cell proliferation and collagen deposition, scar formation, wound contraction, connective tissue remodelling, recovery of tensile strength
Give examples of local factors which can affect wound healing.
Type, size and location of wound Movement within wound Infection Presence of foreign/necrotic material Irradiation Poor blood supply
Give examples of systemic factors which can affect wound healing.
age nutrition systemic disease drugs smoking
