Coagulation

Question 1

What is haemostasis

Answer 1

Cessation of blood loss from damages vessel, followed by repair

Question 2

What 3 phases can haemostasis be broken into

Answer 2

Vascular, platelet and coagulation

Question 3

What happens I’m primary haemostasis

Answer 3

Platelets immediately form a plug at the site of injury

Question 4

What happens in secondary haemostasis

Answer 4

Occurs simultaneously with primary haemostasis
Additional coagulation factors beyond factor VII respond in a complex cascade to form fibrin strands, strengthening platelet plug
Stabilising of clot

Question 5

What happens I’m tertiary haemostasis

Answer 5

Dissolution of fibrin clot

Dependant I’m plasminogen activation

Question 6

What is coagulation

Answer 6

Process by which blood changes from liquid to gel forming a clot

Question 7

What are platelets

Answer 7

Disc shaped, anucleate cellular fragments derived from megakaryocytes

Question 8

What is the pivotal role of platelets

Answer 8

Haemostasis
Forms initial plug
Pivotal role include adhesion, secretion and aggregation

Question 9

What controls synthesis of platelets

Answer 9

IL-6, IL-3, IL-11 and thrombopoietin

Question 10

What do platelets do

Answer 10

Secrete factors that activate other platelets, allow adhesion, cause vasoconstriction
Adhere to vessel wall at damaged site
Platelet aggregation builds up the initial plug

Question 11

What activates platelets

Answer 11

ADP
platelet activating factor 
Adrenaline
Collagen
Thrombin
Immune complexes
High physical shear force

Question 12

What two processes are initiated when blood is exposed to space under endothelium

Answer 12

Changes in platelets, subsequent recruitment of more platelets
The exposure of Subendothelial factors to plasma factor VII, leading to fibrin formation

Question 13

What do vessels do in coagulation

Answer 13

Damage results in exposure of basement membrane - blood now exposed to collagen
Damage results in exposure of vessel wall - blood is now exposed to platelet activating factor
The damage results in exposure
Smooth muscle cells in vessel wall respond to damage by contracting

Question 14

What is factor I and it’d molecular weight

Answer 14

Fibrinogen

340000

Question 15

Factor II

Answer 15

Prothrombin

Question 16

Factor III

Answer 16

Tissue factor

Question 17

Factor IV

Answer 17

Calcium ion

Question 18

Factor V

Answer 18

Proaccelerin

Question 19

Factor VII

Answer 19

Serum prothrombin conversion accelerator (SPCA)

Question 20

Factor VIII

Answer 20

Antihemophillic factor (AHF)

Question 21

Factor IX

Answer 21

Christmas factor

Question 22

Factor X

Answer 22

Stuart-Prower factor

Question 23

Factor XI

Answer 23

Plasma thromboplastin antecedent (PTA)

Question 24

Factor XII

Answer 24

Hageman factor

Question 25

Factor XIII

Answer 25

Fibrin-stabilisation factor (FSF)

Question 26

Role of vitamin k in clotting

Answer 26

Some clotting factors need post-translational modification | This PTM requires vitamin k

Question 27

What do PTMs do

Answer 27

Involved the addition of a COO- to certain Glu residues in clotting factor Results in the formation of several y-carboxy glutamates = Gla

Question 28

What factors need PTM

Answer 28

II, VII, IX, X, Proteins C and S

Question 29

How is thrombin formed in the coagulation cascade

Answer 29

Protrombin is proteolytically cleaved to form thrombin in the coagulation cascade

Question 30

Role of fibrinogen

Answer 30

Fibrinogen can form bridges between platelets, by binding to their GpIIb/IIIa surface membrane proteins Converted to fibrin and cross links with factor XIII to form clot

Question 31

What do tissue factors do

Answer 31

Enables cells to initiate the blood coagulation cascades It functions as the high-affinity receptor for coagulation factor VII Potent initiator that is fully functional when expressed on cell surfaces

Question 32

What is fibrinolysis

Answer 32

Process that prevents blood clots from growing and becoming problematic

Question 33

How does fibrinolysis occur

Answer 33

Plasmin is produced in inactive form plasminogen Plasminogen cannot cleave fibrin, but still has affinity for it, so incorporates into the clot Tissue plasminogen activator and urokinase are the agents that convert plasminogen to active plasmin, thus allowing fibrinolysis

Question 34

What are fibrin clots degraded by

Answer 34

Serine protease called plasmin