5 Haemostasis, Thrombosis and Embolism Flashcards Preview

Semester 2- MoD > 5 Haemostasis, Thrombosis and Embolism > Flashcards

Flashcards in 5 Haemostasis, Thrombosis and Embolism Deck (22)
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0
Q

What does successful haemostasis depend on? (4)

A

Vessel wall
Platelets
Coagulation system
Fibrinolytic system

1
Q

What is haemostasis?

A

The ability to stop bleeding

2
Q

How do blood vessels limit blood loss?

A

Constrict to limit blood flow

3
Q

Describe the process of platelet aggregation

A

ATP => ADP
Thromboxane A2 causes platelet aggregation
Aided by 5HT and PF3

4
Q

How is coagulation regulated? Give an example

A

By thrombin inhibitors
Antithrombin III
Protein C and S

5
Q

What is fibrinolysis? How does it occur?

A

The breakdown of fibrin

Plasminogen is degraded to plasmin by plasminogen activators

6
Q

Give an example of a plasminogen activator

A

Prostacyclin
Nitric Oxide
Thrombomodulin

7
Q

What is ‘thrombosis’?

A

The formation of a solid mass of blood within the circulatory system.

8
Q

Why do blood clots form?

A

Abnormalities of the vessel wall
Abnormalities of blood flow
Abnormalities of blood components

9
Q

What are the features of an arterial thrombus?

A

Pale, granular, lines of Zahn, lower cell content

10
Q

What are the features of a venous thrombus?

A

Soft, gelatinous, deep red, higher cell content

11
Q

What occurs in lysis of thrombi?

A

Fibrinolytic system degrades the thrombus so blood flow is re-established

12
Q

What is propagation of thrombi?

A

Progressive spread of thrombosis

Distally in the arteries and proximally in the veins

13
Q

What is organisation of thrombi?

A

Ingrowth of fibroblasts and capillaries so lumen remains obstructed

14
Q

What is ‘recanalisation’?

A

Bloodflow is re-established but incompletely as channels form through the thrombus

15
Q

How do most embolisms form?

A

Part of a thrombus breaks off and travels in the blood stream to lodge at a distant site.

16
Q

What is an embolism?

A

The blockage of a blood vessel at a site distant from its origin.

17
Q

What forms can embolisms take?

A

Air, amniotic fluid, nitrogen, medical equipment, tumour cells

18
Q

When is a deep vein thrombosis more likely to occur?

A

Post-op
Immobile
Pregnancy
After severe burns

19
Q

How is deep vein thrombosis treated?

A

Intravenous heparin

Oral warfarin

20
Q

When does a fat embolism occur?

A

After a long-bone fracture

21
Q

What does a cerebral embolism result in?

A

A stroke