Platelet Biochemistry

Question 1

What are the 3 roles of platelets?

Answer 1

Adhesion, Activation and Aggregation

Question 2

What role does vWF have?

Answer 2

vWF bind to collagen, and platelets bind to vWF

Question 3

Describe platelet activation?

Answer 3

1) Platelets change shape from smooth to spiculated
2) Increasing surface area
3) New platelets adhere to old ones (PAg) forming platelet plug

Question 4

What is synthesised by activated platelets?

Answer 4

Thromboxane A2

Question 5

Function of Thromboxane A2(TXA2)?

Answer 5

Further platelet aggregation

Question 6

Name platelet receptors for fibrinogen?

Answer 6

GP IIb/IIIa (Bridges between platelets by Fib)

Question 7

What does prothrombin get converted into in homeostasis?

Answer 7

Thrombin

Question 8

3 roles of Thrombin?

Answer 8

1) Fibrinogen –> Fibrin
2) Activates factor XIII to XIIIa
3) Positive feedback causing further thrombin production

Question 9

Essential component of a blood clot?

Answer 9

Fibrin

Question 10

Role of fibrinolytic system?

Answer 10

Prevents blood clots from growing and becoming a problem

Question 11

Outline fibrinolytic system

Answer 11

Plasminogen converted into plasmin, which cleaves fibrin at places to form fragments

Question 12

What is released on cell activation and contains high conc of molecule acting as agonist at P2Y12 receptor?

Answer 12

Platelet dense granules

Question 13

Role of fibrinogen in platelet aggregation?

Answer 13

Cross links between aggregating platelets

Question 14

When do platelet receptors get exposed for fibrinogen?

Answer 14

During platelet activation