Platelet activation

Question 1

Process initiated by blood vessel injury

Answer 1

Exposes collagen, releases VWF, releases tissue factor

Question 2

Platelet adhesion process

Answer 2

Platelets adhere to a foreign surface

Question 3

Initiating factor of platelet adhesion

Answer 3

Exposure of subendothelial collagen

Question 4

Effect of damaged endothelial cells on VWF

Answer 4

release VWF from storage

Question 5

VWF behavior upon release

Answer 5

VWF unrolls and becomes fibrillar

Question 6

Platelet binding site for VWF

Answer 6

GPIbα portion of GP Ib/IX/V

Question 7

Nature of VWF-platelet binding

Answer 7

Reversible binding that ‘tethers’ or decelerates the platelet

Question 8

Role of ADAMTS-13 in VWF binding

Answer 8

Digests unused VWF to localize platelet-VWF interactions

Question 9

Effect of GP VI binding to collagen

Answer 9

Activates internal platelet pathways and releases TXA2 and ADP

Question 10

Process initiated by blood vessel injury

Answer 10

Exposes collagen, releases VWF, releases tissue factor

Question 11

Effect of blood vessel injury on collagen

Answer 11

Collagen is exposed

Question 12

Effect of blood vessel injury on VWF

Answer 12

VWF is released

Question 13

Effect of blood vessel injury on tissue factor

Answer 13

Tissue factor is released

Question 14

Platelet adhesion process

Answer 14

Platelets adhere to a foreign surface

Question 15

Initiating factor of platelet adhesion

Answer 15

Exposure of subendothelial collagen

Question 16

Effect of damaged endothelial cells on VWF

Answer 16

release VWF from storage

Question 17

VWF behavior upon release

Answer 17

VWF unrolls and becomes fibrillar

Question 18

Platelet binding site for VWF

Answer 18

GPIbα portion of GP Ib/IX/V

Question 19

Nature of VWF-platelet binding

Answer 19

Reversible binding that ‘tethers’ or decelerates the platelet

Question 20

Role of ADAMTS-13 in VWF binding

Answer 20

Digests unused VWF to localize platelet-VWF interactions

Question 21

Effect of GP VI binding to collagen

Answer 21

Activates internal platelet pathways and releases TXA2 and ADP

Question 22

Function of TXA2

Answer 22

Binds to TPα and TPβ

Question 23

Function of ADP

Answer 23

Binds to P2Y1 and P2Y12

Question 24

TXA2 and ADP effect on α2β1 (GP Ia/IIa)

Answer 24

Triggers increased affinity for collagen

Question 25

Combined effect of GP Ib/IX/V, GP VI, and α2β1 (GP Ia/IIa)

Answer 25

Firm attachment of platelet to damaged surface and spreading

Question 26

TXA2 and ADP effect on platelets

Answer 26

Activate adjacent platelets via their receptors

Question 27

TXA2 and ADP effect on αIIbβ3 (GP IIb/IIIa)

Answer 27

Provide inside-out activation for platelet aggregation

Question 28

Platelet aggregation process

Answer 28

Platelets adhere to other platelets

Question 29

Role of tissue factor (TF) in aggregation

Answer 29

Triggers thrombin generation, activating PAR1 and PAR4

Question 30

Coat platelet formation

Answer 30

Collagen and thrombin activated platelet integral to cell-based coagulation

Question 31

Function of αIIbβ3 (GP IIb/IIIa)

Answer 31

Binds fibrinogen and VWF, supporting platelet-to-platelet aggregation

Question 32

Changes during aggregation

Answer 32

Platelets lose shape, extend pseudopods, phosphatidylserine flips

Question 33

Effect of aggregation on membrane integrity

Answer 33

Loss of membrane integrity, syncytium of platelet cytoplasm forms

Question 34

Platelet activation triggers

Answer 34

Actin microfilament contraction

Question 35

Intermediate filaments function

Answer 35

Compress granules by moving microtubules inward

Question 36

Phosphatidylserine role

Answer 36

Supports tenase and prothrombinase with ionic calcium

Question 37

α-granule contents

Answer 37

Fibrinogen, Factor V, Factor VIII, VWF

Question 38

VWF function

Answer 38

Stabilizes Factor VIII

Question 39

Granules’ content flow

Answer 39

Through SCCS to plasma membrane

Question 40

Dense granules function

Answer 40

Vasoconstrictors and platelet agonists

Question 41

Lysosome function

Answer 41

Digest vessel wall matrix and debris