Haemostasis

Question 1

How long does it take for a clot to disappear

Answer 1

1 week

Question 2

Clot formation elements

Answer 2

Platelets, vWF, coagulation factors all of which are unactivated under normal circumstances

Question 3

What allows the clot to remain confined to the site of injury

Answer 3

Natural Anticoagulants

Question 4

What makes the clot disappear

Answer 4

Fibrinolytic System

Question 5

Prevention of blood sticking to the wall of the vessel

Answer 5

Endothelial surface of blood vessels produces Heparis, TFPO, thrombomodulin, nitric oxide, prostacyclin

Question 6

Vessel Damage: Platelet Adhesion

Answer 6

Platelets become activated and stick to the subendothelial collagen, Von Willebrand Factor is also introduced

Question 7

Platelets Glycoproteins

Answer 7

Presence of receptors on the platelets which bind to other coagulation factors

Question 8

Platelet Cell Surface Receptors

Answer 8

ADP receptor, Epineprhine, Thrombin, signalling inside the platelet and tells it what to do

Question 9

Dense Granules and Alpha Granules

Answer 9

Dense (ADP/ATP, Calium, serotonin) and alpha granules (VWF and thrombin) contain key molecules which have a significant role in improving clot formation. Degranulation into the open canalicular system.

Question 10

GP Ia/IIa

Answer 10

Bind to collagen

Question 11

GP IIb/IIIa

Answer 11

Fibrinogen

Question 12

GPIb

Answer 12

Von Willebrand Factor

Question 13

Activation of platelet

Answer 13

Via ADP and Epinephrine Receptors resulting in Arachdonic Acid to Thromboxane A2 by Cycloxidase

Question 14

Scramblase

Answer 14

enzyme which flips the membranes to allow aggregrates on the surface

Question 15

Definitive Haemostasis

Answer 15

The formation of a definitive fibrin clot. Small platelet plug with fibrin plug on top of it.

Question 16

Haemophilia B

Answer 16

Factor IX would be deficient

Question 17

Haemophilia A

Answer 17

Factor VIII is deficient

Question 18

Coagulation Cascade

Answer 18

Tissue factor released at the site of injury, VIIa activates factor 10, results in the conversion of prothrombin to thrombin (resulting in the conversion of fibrinogen to fibrin) and the clot forms.

Question 19

Natural Anticogulants TFPI

Answer 19

Switches off Xa and VIIa

Question 20

Natural Anticoagulants Protein C and S

Answer 20

Switches off factor 5a

Question 21

Natural Anticoagulants Antithrombin

Answer 21

Switches off XIa, IXa, VIIIa, Xa and thrombin

Question 22

Fibrinolysis

Answer 22

Endothelial cells produce t-PA and u-PA (plasminogen activator). Cleaves plasminogen into plasmin. The plasmin breaks the clot down and re-distributes it.

Question 23

Fibrin Degradation Products

Answer 23

Formed after the breakdown of the fibrin clot

Question 24

Inhibitors of plasmic

Answer 24

Antiplasmin and macroglobulin

Question 25

Aspirin

Answer 25

Prevents the enzyme of COX from converting Arachadonic Acid to Thromboxane A2 (prevents platelet aggregration)

Question 26

Clopidegral, Prasugrel, Ticagrelor

Answer 26

These prevent activation of the platelet through the ADP receptor. Used in the prevention of stent occlusion.

Question 27

Tibrofibran, Abciximab, Eptifibatide

Answer 27

Prevent the binding of fibrinogen to the platelet

Question 28

Warfarin

Answer 28

Inhibits the action of vitamin K which is required for the production of factors IX, Prothrombin, X, VII. Produces an anticoagulated state. Useful in AF.

Question 29

Heparins (Rivaroxaban, Edoxaban, Apixiban)

Answer 29

Prevents the formation of Xa preventing the formation of thrombin therefore less fibrin is made. Also indirectly inhibit thrombin

Question 30

Dabigatran

Answer 30

Thrombin Inhibitors