Week 7

Question 1

What is the coagulation cascade?

Answer 1

• Damaged blood vessel triggers release of clotting factors.
• Converting Prothrombin to thrombin
• Converting Fibrinogen to fibrin
• Vasoconstriction limits blood flow, platelets for a plug
• Fibrin strand adhere to the plug to form an insoluble clot.

Question 2

Platelets have the ability to stick together what would this be called?

Answer 2

Thrombocytes

Question 3

Platelets contain dense granules, what are they?

Answer 3

Contain phospholipids, triglycerides, cholesterol, ATP, ADP, Serotonin (5HT-which they obtain while passing through GIT) Drive the simulation of coagulation

Question 4

Platlets contain alpha granules, what are they?

Answer 4

Contain secreted proteins as clotting factors, & PDGF

Question 5

Thrombopoiesis

Answer 5

Hemocytoblast, Megakaryoblast, Promegakaryocyte, Megakaryocyte then form platelets
Takes place in bone marrow,

Question 6

What is a platelets life span?

Answer 6

8-12 days - destroyed by tissue macrophage system in spleen. someone without a spleen would struggle to get rid of old platelets, this increases the chances of clotting.

Question 7

Thromocytosis

Answer 7

Increase in platelet count more than 450,000/mm3

Question 8

Thrombocytopenia

Answer 8

Decrease in platelet count less than 150,000/mm3

Question 9

What is ITP (idiopathic thrombocytopenia purpura?

Answer 9

Recognises platelets as non-self, the immune system struggles to destroy them..

Question 10

What happens when something binds to the platelet?

Answer 10

Surface receptors on the platelets

1. Transient tethering
2. Then they would roll, then
3. Activation when the GPVI binds to exposed collagen
4. Release alpha and dense granules
5. Attracting further platelets
6. Aggregate using the fibrinogen

Question 11

What are some of the G protein coupled receptors on a platelet?

Answer 11

There are some G protein coupled receptor - respond to Thrombin(TP), thromboxaneA2 (PAR4-PAR1) and ADP(P2Y1-P2Y12)

Question 12

Why are integrins important in platelets?

Answer 12

Because they are the adhesion molecules

Question 13

What does clopidogrel inhibit?

Answer 13

Activated in Liver

• Interaction between ADP and the P2Y12 G-protein coupled receptor,
• Causing increase of cAMP
• Inhibiting the formation of the clot.

Question 14

What is Clopidogrel?

Answer 14

Potent oral antiplatelet agent used in the treatment of coronary artery disease, peripheral vascular disease, and cerebrovascular disease.

Question 15

What is clopidogrel used for?

Answer 15

Reducing the risk of heart attack or stroke for the second time. Or have circulatory problems due to narrowing and hardening of the arteries.

Question 16

How much Clopidogrel turns into its active metabolite?

Answer 16

15% of the drug through oxidation and 85% of the drug is degraded by esterase’s.

Question 17

What are the limitations of clopidogrel?

Answer 17

• Low efficiency hepatic transformation causes reduced activity and necessity of using high doses.
• Reliance on hepatic processes causes individual variability
• Patients can become resistant after having earlier treatment
• Complexities in therapeutic dosage, slow onset interaction with other drugs and diseases.

Question 18

Prasugrel vs Clopidogrel

Answer 18

Prasugrel has less genes which can affect treatment response,

Question 19

Prasugrel was made in what year

Answer 19

2009 - simpler conversion/ less resistance

Question 20

Tricagrelor was made in what year

Answer 20

2010 - no conversion / less resistance

Question 21

Cangrelor was made in what year

Answer 21

2015 -no conversion/less resistance