Thrombosis and Embolism

Question 1

What is thrombosis

Answer 1

Process leading to the formation of a thrombus

Question 2

What is a thrombus

Answer 2

Solid mass composed of blood constituents which have aggregated together in flowing blood in the lumen of a blood vessels;

Question 3

What are the main constituents of a thrombus

Answer 3

Platelets and fibrin

Question 4

What is thrombosis limited by

Answer 4

Fibrinolysis

Question 5

When does thrombosis become a pathological process

Answer 5

When it isn’t controlled by fibrinolysis

Question 6

How Is a thrombus formed

Answer 6

• VEssel wall is breached
• Circulating platelets aggregate to plug the gap
• Platelets release factors which trigger coagulation cascade
• Coagulation cascade converts fibrinogen to large molecules of insoluble fibrin
• Long fibrin molecules bind together platelets and entrapped red and white cells

Question 7

What controls the size of the thrombus

Answer 7

Fibrinolysis

Question 8

What holds the thrombus together

Answer 8

FIbrin

Question 9

What is the active enzyme which fragments fibrin

Answer 9

Plasmin

Question 10

What is a measure of thrombosis

Answer 10

D-Dimer test

Question 11

What inactive proenzyme does plasma contain

Answer 11

Plasminogen

Question 12

What does plasminogen become

Answer 12

Plasmin

Question 13

What is plasminogen converted to plasmin by

Answer 13

Plasminogen activators

-particularly tissue plasminogen activator (secreted by endothelial cells)

Question 14

What happens in fibrinolysis

Answer 14

When fibrin is formed, plasminogen and tissue plasminogen activator bind to it. The tissue plasminogen activator converts nearby plasminogen to plasmin which degrades the fibrin

Question 15

What are D-dimers and when’re they elevated

Answer 15

Breakdown product of a fibrin mesh

-Increased blood levels in thrombosis

Question 16

What factors contribute to the formation of a thrombus

Answer 16

• Damage to vessel wall
• Slow or turbulent blood flow
• Change in character of blood

Question 17

How does the character of blood change for there to be an increase in the chance of a thrombus

Answer 17

• Increased platelets
• Increased red cell numbers
• Increased viscosity

Question 18

Main cause of thrombus formation in arteries

Answer 18

Vessel wall damage

Question 19

MAin cause of thrombus formation in veins

Answer 19

Stasis of blood

Question 20

Main cause of thrombus formation in ventricles

Answer 20

Chamber wlall damage

Question 21

Main cause of thrombus formation in atrium

Answer 21

Stasis of blood

Question 22

Main cause of thrombus in heart valves

Answer 22

Valve surface damage

Question 23

What does a thrombus in the artery leading to the heart lead to

Answer 23

Angina

Question 24

What does a thrombus in a coronary artery lead to

Answer 24

Heart attack

Question 25

What does a thrombus in an artery leading to the brain lead to

Answer 25

Stroke

Question 26

In a vein, what does an occlusion prevent and so what does this lead to

Answer 26

Prevents drainage of tissues. So blood pools and cannot escape. This leads to congestion and infarction

Question 27

What is organised thrombus

Answer 27

- New vessels grow into the thrombus - VAscular granulation tissue develops - Fibroblasts invade and deposit collagen - Fibrovascular granulation tissue develops

Question 28

What is recanalisation

Answer 28

When vessels link up inside the thrombus

Question 29

What is embolism

Answer 29

Transference of abnormal material by the blood stream with eventual impaction of the material in a vessel distal to its site of origin

Question 30

What are the most important materials to embolism

Answer 30

Thrombus and cancer cells

Question 31

What does a thrombus in an artery or the left side of the heart embolism into

Answer 31

systemic arterial system

Question 32

Where may a thrombus in an artery or the left hand side of the heart go to

Answer 32

``` Brain Lower limbs Mesentric arteries Renal arteries Splenic artery ```

Question 33

Where would a thrombus in a systemic vein eventually embolise

Answer 33

To a pulmonary artery branch

Question 34

What would a pulmonary artery branch thrombus be called

Answer 34

Pulmonary embolus

Question 35

What would a small embolus in a pulmonary artery lead to

Answer 35

small peripheral lung infarct

Question 36

What would a large embolus in a pulmonary artery branch lead to

Answer 36

Sudden death

Question 37

To measure tissue heat, what can you measure

Answer 37

Level of lactate

Question 38

What are some other materials which would embolise

Answer 38

- Fat and marrow - Air - Nitrogen - Amniotic fluid

Question 39

How does nitrogen embolism occur

Answer 39

When you go deep underwater, the solubility of your blood to nitrogen increases so more nitrogen dissolves in bloodstream. IF you go up from the deep water too quickly, the nitrogen becomes 'bubbly' and you get bubbles in blood

Question 40

How does an amniotic embolism occur

Answer 40

Placenta peels off and the amniotic fluid ends up in the blood squamous cells (petal skin cells) which are present in the amniotic fluid can block the blood vessels

Question 41

Difference between infarction and necrosis

Answer 41

Infarction is tissue death (necrosis) due to inadequate supply of oxygen

Question 42

Signs of a previous myocardial infarction

Answer 42

Scarring (white)