Circulation 2- pathological thrombosis and clot formation

Question 1

What is meant by pathological thrombosis?

Answer 1

occurs in absence of cut or traumatic injury

Question 2

What are the main arteries in the heart?

Answer 2

coronary arteries

Question 3

Give the 3 main causes in Virchow’ triad?

Answer 3

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

Question 4

Describe atheroma lipid coming onto surface?

Answer 4

Lipid (and collagen) can also rupture through the intimal surface.
Platelets and fibrin are now exposed to an abnormal substance (lipid and collagen) and turbulent flow and are deposited as a thrombus.
The thrombus blocks the lumen of the coronary artery.
Clot can now form in the stagnant blood behind the thrombus.

Question 5

Describe a bulge of atheroma changing the flow of blood?

Answer 5

Atheroma is a disease of coronary arteries which results in a build up of lipid under the intimal surface.
The lipid can result in abnormal blood flow – can get both slow and turbulent flow.
Slowed blood flow predisposes to fibrin and platelet clumping.

Question 6

Describe how smoking makes it more likely that platelets aggregate?

Answer 6

Smoking cigarettes increases the ‘stickiness’ of platelets (they find it easier to aggregate).
‘Stickier’ platelets make it more likely that a thrombosis occurs.

Question 7

What are the lines of zahn?

Answer 7

Mulitple layers of thrombus and clot

Question 8

What is ischaemia?

Answer 8

when a tissue supplied by an affected artery receives less blood flow

Question 9

What is hypoxia?

Answer 9

decrease oxygenation of tissues

Question 10

What is an infarct?

Answer 10

localised area of dead tissue

Name reserved for necrosis as a result of ischaemia (ischaemic necrosis)

Question 11

What is necrosis?

Answer 11

process of tissue dying in this manner

Question 12

Describe embolism?

Answer 12

a mass of material moving in the vascular system and able to become lodged in a vessel and block its lumen

Question 13

What are most emboli derived from?

Answer 13

thrombi or clots
they break off and go elsewhere in the circulation

Question 14

What is thromboembolism?

Answer 14

when thrombi/ clots embolise

can be arterial or venous

Question 15

How does pulmonary embolism occur?

Answer 15

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, then right heart, then pulmonary trunk, and lodges in pulmonary artery branch

Question 16

How does pulmonary ambolism occur?

Answer 16

embolus blocks pulmonary artery and get pulmonary infarct