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
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
what is the systolic and diastolic blood pressure (BP) of someone with hypertension?
-systolic >160mmHg
-diastolic > 90mmHg
how arteriolosclerosis cause hypertension?
as it causes thickening and loss of elasticity in small arteries and arterioles hence decreasing lumen size of small arteries and arterioles
what does malignant hypertension cause in general? what does it cause occularly?
generally
-smooth muscle cell proliferation
-increased collagen and GAGs
-increased number of concentric layers
-fixed lumen size
ocularly
-microaneurysms of retinal vessels
-haemorrhages of retinal vessels
-optic nerve swelling
