Diseases Flashcards
(99 cards)
What is atherosclerosis?
A progressive disease that is characterised by the build up of plaque within the arteries
What is plaque in the arteries formed from?
Fatty substances, cholesterol, celular waste, calcium and fibrin
What are the two things that can happen to a plaque?
Bleeding into the plaque and formation of a clot on the surface of the plaque
Pathogenesis of atherothrombosis?
Normal -> fatty streak -> Fibrous plaque -> atherosclerotic plaque -> Plaque rupture/ Fissure and thrombosis
What can atherothrombosis cause?
MI, Stroke, Critical leg ischaemia, cardiovascular death
What is ischaemia?
Result of impaired vascular perfusion depriving the affected tissue of nutients
Is ischaemia reversible?
Can be depending on multiple factors including; speed of onset, local demand and duration
What is infarction?
Refers to ischaemic necrosis of a tissue or organ secondary to occlusion/reduction of the arterial supply or venous drainage
What is haemostasis?
Set of well regulated processes that accomplish two important functions;
- maintain blood in a fluid, clot free state in normal vessels
- induce rapid, localised haemostatic plug at site of vascular injury
What is thrombosis?
Formation of a solid or semi-solid mass from the constituents of blood, within the vascular system, during life
Describe thrombogenesis (Virchow’s triad)
Endothelial injury
Hypercoagulability
Changes in blood flow
What is the role of platelets?
Close small breaches in vessel walls
What are the haemostatic contents of platelets?
Alpha granules - adhesion components e.g. fibrinogen, PDGF, anti-heparin etc
Dense granules - ADP
Which molecules to endothelial cells elaborate?
Anticoagulants, antithrombotic, fibrinolytic regulators and prothrombotic molecules
What are the causes of endothelial injury?
Hyperlipidamia, hypertension, smoking, toxins, vasculitis, viruses and immune reactions
What type of flow is blood normally?
Laminar
Which types of blood flow are important in thrombosis?
Turbulence and stasis
What happens when laminar blood flow is disrupted?
Platelets come into contact with the endothelium
Activated clotting factors are not diluted by the normal rapid flow of blood
Inflow of anticoagulant factors is slowed, allowing thrombi to persist
Activation of endothelial cells is promoted
What is hypercoagulability?
Any alteration in the coagulation pathway which predisposes to thrombosis
What are the common sites of arterial thrombi?
Coronary, cerebral and femoral arteries
What are mural thrombi?
Occur on vessel walls
Why are mural thrombi laminated?
There are alternating pale (platelet and fibrin) and dark (RBC/WBC) bands
What is phelbothrobitis?
Inflammation due to venous thrombi
What are the fates of thrombi?
Propagation proximally
Embolisation
Resolution (fibrinolysis)
Organisation