atherosclerosis etc

Question 1

what is ischaemia

Answer 1

loss of blood supply to tissue bc blocked bv 
mostly arteries 
impaired aerobic resp
acut or chronic 
can result in coagulative necrosis

Question 2

what is infarction

Answer 2

area of ischaemic necrosis within tissue or organ
caused by blockage eg aretieral thrombosis/embolism
heals by organisation and fibrosis

Question 3

what is white infarction (cause, shape, look like)

Answer 3

arterial 
sudden obstruction 
shaped according to territory of vessel supply 
pale with red border 
late stage scarring

Question 4

describe red infarction (causes and patho))

Answer 4

sudden obstruction to venous drainage or occlusion of arterial supply to tissue with dual blood supply
congestion -> inc pressure -> rupture small vessels -> blood enters tissues
reperfusion of white infarct

Question 5

what is thrombosis and thrombus

Answer 5

interaction of bv walls, platelets, plasma proteins
balance b/thrombogenesis + thrombolysis
thrombus = clotted mass blood within cardiovascular system

Question 6

what are the functions of the endothelium

Answer 6

barrier b/blood + tissue 
normally antithrombotic (surface molecules + blood molecules inhibit platelet aggregation)
can be prothombotic 
secrete vasodilators/constrictors 
normally resistant to leukocyte adhesion

Question 7

describe function of platelets (where do they flow, adhere, activated by, release what)

Answer 7

flow in centre of stream
dont adhere to endothelium unless injury
activated by collagen exposed after vessel injury
release chemicals to attract more platelets

Question 8

what does virchows triad describe

Answer 8

3 categories that contribute to thrombosis

alterations in blood flow, endothelial wall injury, hypercoaguability

Question 9

what happens in blood flow stasis and why

Answer 9

disruption of laminar flow (bc aneurysms, over-atherosclerotic plaques, atrial fibrilation 
prolonged immobility (bc old, post-surgical, unconscious)

Question 10

what contributes to hypercoagulability of blood

Answer 10

post-operative, genetic, malignancies, high oestrogens, sepsis, obesity, dehydration

Question 11

what causes endothelial wall injury

Answer 11

injury, trauamainjury, direct trauma, inflammation, infection, indwelling catheters smoking, atherosclerosis

Question 12

what are the 3 types of thrombi and their associations

Answer 12

arterial = atherosclerosis/anuerysm 
venous = slow blood + hypercoag 
cardiac = left V bc MI/aneurysm or left A bc fibrilation

Question 13

what are the possible fates of a thrombus and its complications

Answer 13

embolisation, fibrinolysis (breakdown), organisation (replace w/scar tissue) persistence
complications = obstruct blood flow + embolism

Question 14

what is embolism and embolus

Answer 14

embolism = lodging of blockage-causing piece of material inside BV
embolus = intravacular solid, liquid, gaseous mass carried into bloodstream to some site remote from origin
can be athero-emboli, septic, gaseous, fat

Question 15

risk factors for dvt using virchows triad

Answer 15

alterations in blood flow = immobilisation + cardiac failure
endothelial wall injury = trauma, surgical injury, smoking
hypercoagulability = post-op, jigh oestrogen, malignancies…..

Question 16

what is the pathway of pulmonary embolism

Answer 16

dvt forms in lower limb -> travels towards heart -> IVC -> RA -> RV -? PA -> lungs
large emboli = lodge in PA and prevent blood from travelling to lungs

Question 17

consequences of pulmonary embolism

Answer 17

pulmonary infarct (rare bc dual lung blood supply)
pulmonary hypertension => reduction size functional pulmonary vascular bed 
sudden death => inc in burden RHS heart => right ventricular failure

Question 18

what is atherosclerosis and its consequences

Answer 18

accumulation plaque on walls of medium + large arteries (tunica intima)
plaques = central lipid core + fibrous cap
consequences = narrowed vessels = ischaemia,
plaque + acute plaque event = inc ischaemia
plaque + thrombus = infarction

Question 19

risk factors for atherosclerosis

Answer 19

smoking, hypertension, diabetes, dyslipidaemia, age, male, genetics, obesity, lack of exercise, stress

Question 20

7 steps to atherosclerosis pathogenesis

Answer 20

`1. chronic endo injury inc vascular perm with leuk adhesion + thrombotic potential

2. accumulate LDL in intima
3. monocytes migrate -> macs -> engulf lipids -> foam cells
4. platelets adhere
5. release cytokines and growth factor to smooth muscle cells enter intima from media
6. smooth muscle proliferate + produce ECM
7. more accumulation

Question 21

morphological characteristics of atherosclerosis

Answer 21

fat streaks, fibrous plaques, plaque rupture

Question 22

atherosclerosis site of occurrence

Answer 22

elastic arteries (aorta, carotid + iliac arteries)
large + medium muscular arteries (coronary + popliteal + cerebral arteries)

Question 23

consequences of atherosclerosis

Answer 23

thombosis on fibrous plaque, bleeding into plaque, weakening of vessel wall
myocardial + cerebral infarction, aortic aneurysm, preipheral vascular disease

Question 24

what is an aneurysm, causes _ consequences

Answer 24

abnormal focal dilation in wall of vessel or cardiac chamber
bc weajening media (eg bc atherosclerosis)
consequence = thrombosis + rupture

Question 25

prevention and treatment of atherosclerosis

Answer 25

prevention = reduce risk factors, prophylatic medication (aspirin + statins) 
treatments = statins = regression of atherosclerotic plaque, stents (inc lumen size), bypass surgery (HDL levels improve and inc removal of bad cholesterol