10.17.18 Platelet Production and Function

Question 1

Platelets are normally made in the bone marrow from progenitor cells known as ___

Answer 1

megakaryocytes

Question 2

DNA replication continues, but neither the nucleus nor the cell undergoes division

Answer 2

endomitosis

Question 3

What does endomitosis produce?

Answer 3

Polyploid cell

Question 4

Synthesis of this is static and not regulated; made in liver

How are plasma concentrations regulated?

Answer 4

TPO

Platelet production rates and by the total mass of platelets and MK

Question 5

What is the job of GPIa-IIa

Answer 5

binds collagen

Question 6

What is another name for GPIa-IIa

Answer 6

a2B1

Question 7

What is the job of GPIIb-IIIa

Answer 7

binds fibrinogen

Question 8

What is another name for GPIIb-IIIa

Answer 8

a2bB3

Question 9

What is the job of GPIb-IX-V

Answer 9

binds von Willebrand factor

Question 10

What is the job of GPVI

Answer 10

activates platelets by binding to collagen

Question 11

Platelets stick to injured vessel wall via GP Ib-IX-V binding to VWF

Answer 11

Adhesion

Question 12

Resting platelets come in contact with agonists that bind to receptors-signaling occurs-platelets change shape, secrete and activate their GP IIb-IIIa integrins

Answer 12

Activation

Question 13

Platelets stick to each other via fibrinogen bridges binding to activated GP IIb-IIIa

Answer 13

Aggregation

Question 14

Platelets release granular contents and potentiate clotting

Answer 14

Secretion

Question 15

Platelet receptors are GP Ia/IIa and GP VI

Answer 15

Collagen

Question 16

Platelet receptors are P2Y12 and P2Y1

Answer 16

ADP

Question 17

Platelet receptor is PAR-1

Answer 17

Thrombin

Question 18

Platelet receptor is a GPCR

Answer 18

Thromboxane

Question 19

What keeps platelets from sticking to normal endothelium?

Answer 19

1. Nitric Oxide
2. Exto-ADPase
3. Prostacyclin

Question 20

How do you diagnose Qualitative Platelet Disorders?

Answer 20

Prolonged bleeding time via PFA-100

PT/PTT/TCT should be normal

Question 21

What are congenital reasons for Qualitative Platelet Disorders?

Answer 21

1. Bernard-Soulier

2. Glanzmann’s Thrombesthenia

Question 22

What are acquired reasons for Qualitative Platelet Disorder?

Answer 22

1. Uremia
2. ASA, NSAIDs
3. Myeloproliferative disease

Question 23

This is a defect in Ib/IX on platelet surface so there’s no adhesion

Answer 23

Bernard-Soulier

Question 24

this is a defect in IIb/IIIa on platelet surface so there’s no aggregation

Answer 24

Glanzmann’s thrombaesthenia

Question 25

What are the symptoms of platelet hypofunction like?

Answer 25

Same defects of primary hemostasis

1. Heavy bleeding
2. Mucocutaneous bleeding (oozing and bruising)
3. Petechia
4. Purpura
5. Abnormal platelet aggregation leading to stroke/heart attack