Lecture - Blood (Haemostasis #2 Coagulation)

Question 1

So with endothelium, what does it do if it’s:

1. Normal
2. Injured or activated
3. Absent

Answer 1

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Question 2

1. With what two things that platelets have receptors for, can platelets adhere?
2. What 4 things does platelet activation result in?

(what two things constrict vessels?)

Answer 2

Serotonin and TXA2

Question 3

What do platelets provide that is needed for coagulation?

The platelet plug has little strength but what will it do and what is it essential for?

Answer 3

Phospholipid

Question 4

What is blood coagulation? What does it lead to the formation of? What does that trap?

Answer 4

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Question 5

1. What’s the starting point of the intrinsic and extrinsic pathway?
2. Which one is more important?
3. What step of the intrinsic pathway does extrinsic pathway physiological activate?
4. Where do the two pathways overlap?

Answer 5

1. The tissue factor vs everything being in blood
2. Extrinsic
3. Factor 11
4. Factor 10 onwards

Question 6

Extrinsic pathway:

1. What does tissue factor activate?
2. Where is tissue factor expressed? (2)
3. Slow activation of FX to ____ and Prothrombin (II) to Thrombin (____) results in activation of _____, _____, ______ and more platelets activated

Answer 6

3. Slow activation of FX to Xa and Prothrombin (II) to Thrombin (IIa) results in activation of FVa, FVIIIa, FXIa and more platelets activated

Question 7

How do you go from factor 11a to fibrin? (intrinsic, since extrinsic is like 7 to 7a and then 10 to 10a but like 7a also goes to form 11a)

Answer 7

Factor 11a will convert 9 to 9a with the 8a help and Ca++

**Remember, Factors 2, 7, 9 and 10 need Ca++***

Then 9a will convert 10 to 10a with 5a help and Ca++

Then you convert prothrombin to thrombin and the thrombin will go to three places: factor 13, fibrinogen or to bind to thrombomodulin to activate protein C to Ca

Question 8

1. Assembly of coagulation enzyme complexes occurs on what?
2. What binds proteins to the platelet surface?
3. What are cofactors 5a and 8a doing?

Answer 8

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Question 9

What is the source of coagulation factors (2)

Answer 9

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Question 10

1. Four coagulation factors (enzymes) must bind Ca++ and attach to activated platelet surfaces to achieve full functional activity - what are the 4 and what are the 2 inhibitors?
2. What does binding of the Ca++ do?
3. Why is Vit K needed to convert these 6 coagulation factors into functional proteins?
4. Explain what warfarin does

Answer 10

4. So to go from glutamic acid on these 6 factors to gamma-carboxyglutamic acid, you have carboxylase and I think Vit K is its cofactor. This Vit K will go from epoxide and get reduced in the cycle. Epxoide reductase is needed to bring it from the used epoxide to reduced state. Warfarin will inhibit that enzyme so you don’t get the Ca binding and thus less clotting, probably

Question 11

1. Explain the structure of fibrinogen
2. What three things happen in polymerisation? Can you now see why factor 13a is imp (thrombin turns that from 13 to 13a)

Answer 11

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Question 12

What are the two main inhibitors for coagulation, what do they inhibit and how do they work/are activated? What do they stop

Answer 12

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Question 13

What is the thrombin burst important for?

Answer 13

The quality of fibrin you’ll make

Question 14

What are the three activators of fibrinolysis and what are the two inhibitors? What does plasmin do?

Answer 14

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Question 15

Key points about fibrinolysis:

1. Plasminogen can be activated to plasmin - what is that?
2. What does plasminogen bind to?
3. If large amounts of t-PA are present while a clot is
   forming the t-PA will also bind to…?
4. Normal venous endothelium is able to release…..

Answer 15

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Question 16

How is fibrin mesh kept localised to where the endothelium is damaged/gone?

Answer 16

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Question 17

Normal endothelium:

1. What thing coats the surface to not allow platelets to adhere?
2. 2 things are produced by endothelium to dilate vessels and inhibit platelet activation - what are they?
3. What does the velocity of flow being faster in centre of BV do?

Answer 17

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Question 18

Activated endothelium:

1. What is expressed to make platelets adhere?
2. What is produced by adjacent endothelium to cause vasoconstriction?

Endothelial cells lost:

3. What two things happen to cause vessel constriction?
4. What two things things cause platelet adhesion? (well, 3 more like)
5. Platelet activation and release reaction - what three things esp are released?
6. Activation and aggregation of more platelets forms what?

Answer 18

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