Circulatory Disease (OP4103) Flashcards
(27 cards)
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
what happens during the intermediate lesion of atheroma formation?
-fibrous cap is formed of smooth muscle cells between endothelium and macrophages and amongst macrophages
-macrophage death occurs
-formation of lipid droplets
what are the characteristics of an advanced lesion in atheroma formation?
-elevated areas of intimal thickening
-firm and dome shaped bulging into the lumen
-contains a central core of lipid, necrotic mass
-contains a fibrous plaque of macrophages and collagen
risk factors for developing atherosclerosis
-age
-gender
-hypertension
-high plasma cholesterol
-diabetes
-smoking
-lifestyle: lack of exercise, obesity, stress
what are the consequences of atherosclerosis?
-infarction/ ischaemia
-thrombosis
-aneurysms
-atheromatous embolism
-haemorrhage into plaque
-chronic inflammation
how can ischaemia/ infarction be treated?
by-pass surgery, thrombolytic drugs
what can cause hemianopia?
stroke, where half your vision is lost
what is an aneurysm? what does it usually affect?
a weakening of arterial wall causing a distortion/ outward bulge. Can cause a medial thinning beneath the plaque known as an atherosclerotic aneurysm
-usually affects aorta and other muscular arteries
give the risk factors of hypertension
-high salt intake
-high alcohol intake
-coffee
-smoking
-stress
-cold environment
what is associated with atherosclerotic vascular disease?
hypertension
