Overview haem, plug formation, coagulation cascade

Question 1

Outline platelet plug formation?

Answer 1

1) Damage BV leads exposure collagen
2) Adhesion platelets to collagen directly
through glycoprotein 1a leads exposure
glycoprotein IIb./IIIa
3) VWF binds collagen through IIb/IIIa
glycoproteins
- increases platelet adhesion
4) Platelet contains 2 types granules:
- electron dense granules
- alpha granules
Electron dense granules release:
ADP/ATP, serotonin and calcium
ADP acts on P2Y1/P2Y12- lead further
activation
ATP binds P2X1
5) Thrombin binds to PAR1 and PAR4-
platelet activation
6) Activation of platelets:
- change shape from discoid to spiculated/
pseudopodia
- increase SA platelet
7) Activation platelets lead increase
expression IIb/IIIa
8) Fibrinogen secreted alpha granules bind to
receptors
- new platelets adhere old ones- platelet
aggregation
9) Platelets produce thromboxane A2
- aid in vasoconstriction
- reduced blood flow aids forming primary
haemostatic plug
10) Thromboxane and serotonin stimulate
vasoconstriction – reduced blood flow
- aid in forming primary haemostatic plug

Question 2

What initiates platelet plug formation?

Answer 2

Exposure of collagen

Question 3

What receptors are involved?

Answer 3

Platelets directly to glycoprotein 1a leads exposure of glycoprotein IIb./IIIa
Von Willebrand Factor binds to collagen through IIb/IIIa glycoprotein increases platelet adhesion

Question 4

What granules do platelets contain?

Answer 4

Electron dense
Alpha granules

Question 5

What do electron dense granules release?

Answer 5

ADP/ATP
Serotonin
Calcium

Question 6

What does ADP act on? Function?

Answer 6

P2YQ- further activation

Question 7

What does thrombin bind to?

Answer 7

PAR1, PAR4
Result platelet activation

Question 8

What does activation of platelets cause?

Answer 8

1) Change shape from discoid to
spiculated/spikey shape with pseudopodia
- increase SA platelet
2) Activation platelets lead increase expression
of Iib/IIIa
- fibrinogen secreted from alpha granules bind
to it which
- new platelets adhere old ones- platelet
aggregation
3) Platelets produce thromboxane A2
- play part vasoconstriction
- reduced blood flow- aids forming primary
haemostatic plug

Question 9

What stimulates vasoconstriction?

Answer 9

Thromboxane and serotonin
Reduce blood flow- aid forming primary haemostatic plug

Question 10

Outline plug formation

Answer 10

Question 11

Outline coagulation cascade?

Answer 11

1) Injury blood vessel leads activation factors
12, 11, 9, 10
2) Activation factor 10 (help factor 5, converts
prothrombin to thrombin)
3) Thrombin converts fibrinogen to fibrin
4) Factor 13a and fibrin form fibrin clot

Only thing in extrinsic pathway is TF activating factor 7 to 7a
Factor 7a plays role converting factor 10 to 10a

Question 12

What is needed for function 9a and 10a?

Answer 12

Phospholipid and calcium exposure

Question 13

Draw coagulation cascade

Answer 13

Question 13

Draw coagulation cascade

Answer 13

Question 14

Explain fibrinolytic system? (remove clot)

Answer 14

Intrinsic factor 7a + extrinsic action tissue plasminogen
- converts plasminogen into plasmin
Plasmin degrades fibrin