Session 5 Lecture 2

Question 1

What are the overview principles of haemostasis?

Answer 1

• Prevent bleeding

- Prevent unnecessary coagulation, allow blood to flow

Question 2

What bare the basic steps to preventing bleeding?

Answer 2

• Make a clot
• Control clotting
• Break it down

Question 3

What are the essentials for haemostasis?

Answer 3

• Keep blood moving
• Blood vessels
• Platelets
• Coagulation factors
• Anticoagulant factors

Question 4

What produces platelets and where?

Answer 4

Magakaryocytes produce platelets in the bone marrow

Question 5

What is the normal life span of platelets?

Answer 5

7-10 days

Question 6

What are the different steps that platelets have to go through in order to form the platelet plug?

Answer 6

Adhesion
Activation
Aggregation

Question 7

What happens in platelet adhesion?

Answer 7

• Damage to vessel wall
• Exposure of underlying tissues
• Platelets adhere to collagen via vWF/receptor

Question 8

What happens during platelet activation?

Answer 8

• Secrete ADP, thromboxane and other substances to become activated and activate other platelets
• Involved in clotting cascade
• Provide some coagulation factors

Question 9

What happens in platelet aggregation?

Answer 9

Cross linking of platelets to form a platelet plug

Question 10

What is the clotting cascade?

Answer 10

Amplification system activation of precursor proteins to generate thrombin (IIa)

Question 11

What is the function of thrombin in the clotting cascade?

Answer 11

Converts soluble fibrinogen into insoluble fibrin which stabilises the platelet plug.

Question 12

How is the clotting cascade controlled?

Answer 12

• Natural anticoagulants to inhibit activation

- Clot destroying proteins which are activated by the clotting cascade

Question 13

Where are the coagulation factors and natural anticoagulants made?

Answer 13

Liver

Question 14

Give some examples of coagulation factors

Answer 14

Fibrinogen, prothrombin, factor 5,7,8,9,10,11,12,13 and tissue factor

Question 15

Give examples of natural anticoagulants?

Answer 15

Protein C, protein S and antithrombin

Question 16

What is PT (prothrombin) time a measure of?

Answer 16

Extrinsic pathway

Question 17

What is APTT a measure of?

Answer 17

Intrinsic pathway

Question 18

What would a lab result be if factor 8 is not working properly?

Answer 18

APTT is prolonged

Question 19

What would a lab result be if factor 7 is not working properly?

Answer 19

PT is prolonged

Question 20

What would a lab result be if factor 5 is not working properly?

Answer 20

APTT and or PT are prolonged

Question 21

What is the thrombin burst?

Answer 21

Small amount of thrombin causes a large amount of thrombin to be released

Question 22

What is the von Willebrand factor?

Answer 22

Involved in platelet adhesion to the vessel wall, platelet aggregation and also carries factor 8.

Question 23

What is fibrinolysis?

Answer 23

The process breaking down a clot

Question 24

What is needed for fibrinolysis to occur?

Answer 24

Plasmin

Question 25

What does plasmin do?

Answer 25

Plasmin breaks fibrin into fibrin degradation products

Question 26

What would happen if someone is deficient in natural anticoagulants?

Answer 26

Clot excessively

Question 27

What is the function of natural anticoagulants?

Answer 27

Stop further coagulation.

Question 28

What are bleeding disorders due to?

Answer 28

Due to abnormality in the vessel wall, platelets or coagulation factors

Question 29

How do you get a bleeding disorder?

Answer 29

Inherited or acquired

Question 30

Give an example of a congenital coagulation factor disorder

Answer 30

``` Haemophilia A (factor 8) Haemophilia B (factor 9) ```

Question 31

Give examples of acquired coagulation factor disorders

Answer 31

Liver disease, vitamin K deficiency and warfarin

Question 32

What are the two different types of platelet disorders?

Answer 32

Qualitative - abnormal platelet activity | Quantitative - reduced platelet count

Question 33

Why might someone have reduced platelet count?

Answer 33

- Reduced production | - Increased removal

Question 34

Hey might someone have increased removal of platelets?

Answer 34

- Non-immune destruction - Immune destruction - Splenic pooling

Question 35

How can you determine the cause of reduced platelet count?

Answer 35

Bone marrow biopsy

Question 36

What is thrombocytopenia?

Answer 36

Reduced platelet count

Question 37

Why might someone have reduced platelet production?

Answer 37

- B12 folate deficiency - Cancer or fibrosis - Drugs - e.g. chemotherapy - Viruses - e.g. HIV

Question 38

What is petichae?

Answer 38

Small bleeds into the skin

Question 39

What is purpura?

Answer 39

A rash of purple spots on the skin caused by internal bleeding from small blood vessels