Inflammation Flashcards
What is inflammation?
Complex biological reaction that occurs in vascularized tissues in response to harmful stimulus.
Recruits cells and molecules for defense from circulation to site of injury.
What are the 5 signs of inflammation?
Pain - chemicals released at nerve endings Redness - increased blood flow to site Immobility - fluid accumulation Swelling - fluid accumulation Heat - increased blood flow to site
What system controls inflammation?
Immune system
Describe the immune system.
A system of biological processes and structures to protect against disease.
What is the 2 parts of immune system called?
Innate immune system
Adaptive/acquired immune system
Describe the innate immune system (4 points).
This is the first-line of defence and responds quickly to invaders but defends in a non-specific manner.
It can physically act to confine the invader and stop spread in the body.
Response in the same on re-exposure.
What are the 4 barriers of the innate immune system?
Anatomic/physical barriers
Inflammatory barriers
Physiological barriers
Phagocytic barriers
Describe the adaptive/acquired immune system.
Second line of defense with a slower immune response. Able to retain immunological memory hence faster and more specific response upon re-exposure. This system involves high specific cells and processes.
What are the 4 features of the adaptive immune system?
Immunological memory
T cells and B cells
Antigen specific
Self/non-self recognition
Why is the type of response involved in adaptive immune system called antigen specific?
Bodies can generate antibodies to specific antigens therefore, when we are re-exposed to the antigen, we have those antibodies in our immunological memory that can help target them more quickly.
What is the role of HLA/Human Leukocyte Antigen?
To present foreign antigens to elicit T cell response.
What is the role of MHC Class 1?
The major histocompatibility complex (MHC) class I antigen plays an important role in alerting the immune system to virally infected cells.
Two types of inflammation. Chronic and Acute. Describe each.
Acute inflammation has a rapid onset and short duration and is the initial response of the body to harmful stimuli. Inflammation ceases when stimuli removed.
Chronic inflammation has a slow onset and prolonged duration.
Give 3 examples of what can cause acute inflammation.
Infection, trauma/injury, allergic reaction, burns, chemical irritants.
Give 3 examples of causes of chronic inflammation.
Cancer, cardiovascular disease, lupus, fibromyalgia, autoimmune disease, neurological disease.
Give a short summary of what happens during acute inflammation.
Plasma cells and WBCs move into the affected area from the blood. Neutrophils are the predominant WBCs. Once these arrive at site, a cascade of biochemical events enhance immune response. Biochemical response can involve the vascular system and recruit other cell types.
What are the two stages in acute inflammation?
Vascular stage
Cellular stage
What causes chronic inflammation to develop?
When causative agent in acute inflammation is not resolved.
Describe chronic inflammation.
Prolonged duration.
Stimulus is ongoing - simultaneous cycle of destruction and repair of tissue.
What WBC is involved in acute inflammation?
Neutrophils
What WBC is involved in chronic inflammation?
Macrophages and lymphocytes
What is the role of macrophages in inflammation?
Responsible for phagocytosis.
Secreting pro-inflammatory mediators e.g. cytokines.
Describe role of lymphocytes.
There is B and T lymphocytes.
T lymphocytes activate macrophages and aids in dealing with pathogens.
B lymphocytes produce antibodies that help fight against infectious agent.
Macrophages involved in phagocytosis. What are the 4 different stages of phagocytosis.
Attachment, ingestion, killing, degradation
What happens if tissue is not repaired in chronic inflammation? What is the consequence of this condition?
Fibrosis.
It is the pathological form of wound healing. Leads to the deposition of connective tissue or extracellular matrix material which renders parts of an organ or tissue as non-functional.
What are the 3 causes of chronic inflammation?
Prolonged exposure to toxic agent.
Persistent injury/trauma.
Auto-immune disease.
Give example of 3 autoimmune illnesses which can cause chronic inflammation.
Lupus
Rheumatoid arthritis
Psoriasis
What are the 2 mediators of inflammation?
Describe them.
Cellular mediators - preformed and stored in granules.
Plasma derived mediators - components of coagulation, kinin, fibrin etc
Give examples of cellular mediators.
Prostaglandins, thromboxanes and leukotrienes - bioactive lipids - are oxygenated metabolites of arachidonic acid (eicosanoids) which contribute to inflammation.
What is Arachidonic acid (AA)?
It is a component of phospholipid bilayers. Consists of 20-carbon polyunsaturated fatty acids and 4 double bonds.
What enzyme liberates arachidonic acid from cell membrane/phospholipids?
Phospholipase A2 (PLA2)
How many isoenzymes are in the COX family? Name them.
COX1
COX2
COX3
What are the two active sites of COX-1 and COX-2 enzymes?
Both have 2 active sites.
- Cyclooxygenase activity - converts AA to prostaglandin G2 (PGG2)
- Peroxidase activity - reduction of PGG2 to PGH2.
What prostaglandin is a precursor for other different prostaglandins?
Prostaglandin H2.
Name some therapeutic COX inhibitors.
Aspirin
NSAIDs - Naproxen, Ibuprofen, Celecoxib
What are 3 prostaglandin synthase enzymes found in cells and tissues.
Prostacyclin synthase - makes PGI2
Thromboxane A synthase - makes TX2
Prostaglandin D synthase - makes PGD2
Where is prostacyclin synthase found and what is its function?
Endothelial cells
Inhibits platelet aggregation, vasodilator
Where is thromboxane A synthase found and what is its function?
Platelets
Induces platelet aggregation, vasoconstrictor
Where is Prostaglandin D found and what is its function?
Brain and mast cells
Contraction of bronchial airways, regulates body temp (during sleep)
