Circulation 2

Question 1

Describe Virchow’s triad

Answer 1

3 predisposing factors for thrombus formation

Changes in intimal surface of a vessel
Changes in pattern of blood flow
Changes in blood constituents

Question 2

Example 1

Answer 2

Coronary artery thrombosis
Smoking cigarettes increases ‘stickiness’ of platelets (easier to aggregate)
Alteration in properties of blood

(change in blood constituents, part of Virchow’s triad)

Question 3

Example 2

Answer 3

Atheroma - coronary artery disease results in build up of lipid under intimal surface
Slow and turbulent flow - abnormal flow
Slow blood flow predisposes to fibrin and platelet clumping

(Change in pattern of blood flow, part of Virchow’s triad)

(Cigarette smoking/high lipid in the blood can predispose to atheroma in coronary arteries)

Question 4

Example 3

Answer 4

Lipid (and collagen) can rupture through intimal surface

(Change in intimal surface part of Virchow’s triad)

Question 5

Simplified examples

Answer 5

Changes in intimal surface of vessel (atheroma lipid accumulating on surface)

Changes in pattern of blood flow (bulge of atheroma changing flow of blood)

Changes in blood constituents (smoking increases platelets aggregating)

Question 6

Explain the terms ischaemia, hypoxia, anoxia, necrosis and infarction

Answer 6

poor blood flow= ischaemia
decreased oxygenation of tissues =hypoxia
Severe ischaemia and hypoxia cause localised area of dead tissue = infarct
Tissue dying = necrosis
State of total oxygen deprivation within tissues or organs = anoxia

Question 7

give example of each term

Answer 7

Obstruction of artery can lead to ischaemia. hpoxia, anoxia, infarct (necrosis)

Question 8

Effect of ichaemia of different tissue

Answer 8

Coronary artery thrombosis – infarct in heart
Cerebral artery thrombosis – infarct in brain
Mesenteric artery thrombosis – infarct in gut

Question 9

Explain the term embolism

Answer 9

mass of material moving in vascular system gets lodged in vessel and block lumen
Most derived from thrombi or clots
Break off and go elsewhere in circulation

(When thrombi/clots embolise it is called thromboembolism)

Question 10

Discuss example of embolism

Answer 10

Pulmonary embolism

Sluggish flow in leg veins leads to thrombosis and clot formation
Part of thrombus (and clot) breaks off and travels up vein
Embolus passes into inferior vena cava, right heart, pulmonary trunk, lodges in pulmonary artery branch
Embolus blocks pulmonary artery, causes pulmonary infarct

Question 11

Describe Physiological and Pathological thrombosis

Answer 11

Physio - Normal after cut or other injury
Patho - Occurs in absence of cut or traumatic injury (due to virchows triad)