Lecture37: Platelets And Thrombopoiesis

Question 1

What is the origin of platelets?

Answer 1

Megakaryotes in the bone marrow

Question 2

How long do platelets live?

Answer 2

10 days

Question 3

What are GPs (Polymorphic glycoprotein molecules) involved in?

Answer 3

Platelet adhesion

Question 4

What is the peripheral clear region in the cytosol called?

Answer 4

Hyalomere

Question 5

What is the central darker region in the cytosol called?

Answer 5

Granulomere

Question 6

What is the Hyalomere cytoskeleton formation?

Answer 6

15 microtubules arranged in parallel

Question 7

Does the Hyalomere have Actin and Myosin?

Answer 7

Yes

Question 8

What is the Actin and Myosin Function in the Hyalomere?

Answer 8

Platelet movement and retraction

Question 9

What does the OCS (open canalicular system) connect to in the Hyalomere?

Answer 9

Invaginations of the plasmalemma

Question 10

What does the OCS do?

Answer 10

Entry of external elements and storage of GPs, as well as filopodia formation

Question 11

What does the DTS do?

Answer 11

Calcium release

Question 12

What are the granules that the Granulomere displays?

Answer 12

Alpha, delta, and Lambda

Question 13

What does the Granulomere do?

Answer 13

Has enzymes that produces ATP and consume oxygen

Question 14

What is the Alpha Granule in charge of?????

Answer 14

Coagulation, anticoagulation

Question 15

What is the delta granules in charge of?

Answer 15

Serotonin and ATP/ADP

Question 16

What do the GPs do in the First step of platelet adhesion?

Answer 16

They bind to collagen and vWF

Question 17

What happens in stage 2 (platelet shape changes) ?

Answer 17

The extra cellular calcium influxes and so intracellular calcium releases

Question 18

What binds the GP2 receptors in aggregation?

Answer 18

Fibrinogen

Question 19

What happens to form the secondary hemostatic plug?

Answer 19

Fibrinogen broken down by thrombin to form fibrin, and thus stabilize

Question 20

What are the Antiplatelet agents?

Answer 20

TXA2 inhibitors

Question 21

Which 2 factors does antithrombin 2 inhibit?

Answer 21

2a and 5a

Question 22

What does heparin do?

Answer 22

It’s an anticoagulant by enhancing antithrombin 3 activity

Question 23

What does protein C inhibit?

Answer 23

Factors 5 and 8

Question 24

What does prostacyclin inhibit?

Answer 24

It’s a vasodilator, thus it inhibits platelet activation

Question 25

Does NO inhibit platelet adhesion?

Answer 25

Yes

Question 26

What maintains an anti thrombotic surface??

Answer 26

TFPI (Tissue-Factor Pathway Inhibitor)

Question 27

What does Vitamin K do?

Answer 27

It’s deficiency causes bleeding