Circulatory Disease (OP4103) Flashcards
what is coagulation?
formation of a clot due to activation of coagulation cascade
what is thrombosis?
formation of a clot in situ in an intact blood vessel
whats a thrombus?
an abnormal mass attached to a vessel wall
what is an embolus?
an abnormal mass (blood clot) thats freely floating
what happens in haemostasis?
- primary haemostasis - local vasoconstriction
- platelet plug formation via aggregation
- fibrinolysis which dissolves the clot once blood vessel integrity has been restored
what are the steps in activation of the coagulation cascade?
- intrinsic pathway where factor XII is activated
- extrinsic pathway where thromboplastin is released
- factor X activated
what are the factors in virchows triad that predispose thrombosis?
-injury to the endothelial lining
-slowing/ changes of blood flow
-changes in blood constituents
what are the steps in thrombosis that show how platelets have a role in it?
- adherence of platelets
- aggregation of activated platelets
- release of thromboxane A2 and ADP
- additional platelets are recruited
thrombin is formed - thrombus is stabilised by fibrin
give 6 consequences of thrombi
- disintegration of small thrombi
- infection
- propagation
- organisation/ recanalisation
- vessel occlusion of ischaemia or infarction
- formation of emboli
What is an embolism? what is the most common type called?
a passage of material through circulatory system capable of obstructing the lumen and can be either pulmonary or systematic
-most common is thromboembolism
what is a pulmonary embolism?
an emboli of venous origin that blocks pulmonary arteries
what are the common sites of infarction from arterial emboli?
-brain
-intestine
-lower extremity
-kidney
-heart
what are the sources of venous and arterial emboli?
-atheroma
-infection
-fat in long bone fracture post trauma
-gas e.g. gas bubbles in the blood
-latrogenic - IV fluid or drug abuse
-amniotic fluid
-tumour
what are the three main stages of atheroma formation?
- early initial lesion
- intermediate lesions
- advanced lesion
what happens during the initial lesion of atheroma formation?
fatty streak is formed and is
-subendothelial
-focal, small and non-destructive
-occurs in areas of branching
-contains lipid filled foamy macrophages