L14 Blood Coagulation

Question 1

Clotting is where the ______ becomes _____ by conversion of soluble ____ to insoluble _______.

Answer 1

fluid blood
semisolid jelly-like
fibrinogen
fibrin

Question 2

What are the basic mechanisms of clotting?

Answer 2

-Formation of prothrombin activator
(in response to vessel wall injury)
-Conversion of prothrombin to thrombin by prothrombin activator
-Conversion of fibrinogen to fibrin by thrombin
-Polymerization & formation of a stable fibrin meshwork that entangles blood cells

Question 3

What are the coagulation factors? (12)

Answer 3

1.Fibrinogen
2.Prothrombin
3.Tissue factor
4.Ionic calcium
5.Proaccelerin
6.Proconvertin
7.Anti hemophilic globulin
8.Christmas factor
9.Stuart Prower
10.AHF C
11.Hageman factor
12.Fibrin stabilizing factor

Question 4

Vitamin K is required for the normal synthesis of factors ________.

Answer 4

prothrombin
proconvertin
christmas factor
stuart prower factor

Question 5

Liver diseases _____ fibrinogen & prothrombin to low levels & causes ____ tendency.

Answer 5

decrease
bleeding

Question 6

Vitamin K deficiency causes Vit K ______ factors to _____ & cause _____ prothrombin time.

Answer 6

dependent
decrease
prolonged

Question 7

Coagulation occurs by 2 mechanisms such as ?

Answer 7

Intrinsic pathway
Extrinsic pathway

Question 8

Intrinsic pathway is initiated by ____ of blood to a _____-charged surface such as _____ or ____.

Answer 8

contact
negatively
glass
collagen

Question 9

Extrinsic pathway is initiated by ________ which is a _____, liberated by injured tissue.

Answer 9

tissue factor
lipoprotein

Question 10

1)Factor _____ greatly accelerates the ____ activity of stuart-prower factor.

2) ______ act as the surface on which reactions occur

3) ____ is the actual protease that causes splitting factor ______ to _____ in the presence of ____ ions.

4) ____ has a positive feedback effect.

Answer 10

Proaccelerin
protease

Phospholipids

Stuart-prower
prothrombin
thrombin
calcium

Thrombin

Question 11

What is the formation of fibrin?

Answer 11

Fibrinogen-> fibrin monomers->fibrin polymers->stable fibrin clot

Question 12

What are the importance of intrinsic pathway of coagulation?

Answer 12

• an enzyme cascade system
  -thrombin has autocatalytic effect
  -each factor is an enzyme that gets activated by the earlier enzyme
  -essential for normal clotting process (1-6 min for clot to form )

Question 13

What are the importance of extrinsic pathway of coagulation?

Answer 13

-Rapid - takes 15 secs to form clot
-Most factors involved are Vit K dependent factors
-Assessed by prothrombin time

Question 14

Importance of anti hemophilic globulin factor are?

Answer 14

-Essential for activation of stuart prower factor
-deficiency will cause classical hemophilia
-Hemophilia is a X-linked hereditary disorder

Question 15

Role of calcium ions in blood coagulation are?

Answer 15

-essential for clotting to occur
-required for all reactions ( except first two in intrinsic pathway )
-prevented by removing from blood outside of body ( in vitro )
-calcium level has to fall to low levels to affect clotting ( in vivo )

Question 16

________ mechanisms ( clotting tendency of blood ) is balanced by ______ mechanisms
( prevent clotting inside blood vessels ).

Answer 16

Pro-hemostatic
Anti-hemostatic

Question 17

Factors that favor clotting within blood vessels are?

Answer 17

-sluggish blood flow ( in veins of legs after surgery, prolonged bed rest )
-damaged endothelium by atherosclerotic plaques

Question 18

Fibrinolysis is the ____ of formed clot by _____.
Fibrin converted to ____ (FDP).
Plasmin is the active form of ______.
Plasminogen is activated by tissue ________ from endothelial cells.

Answer 18

lysis, Plasmin
Fibrin degradation products
plasminogen
plasminogen activator

Question 19

Significance of fibrinolysis?

Answer 19

-Fibrinolysis is initiated at the same time as clotting
-Prevents extensive clotting of blood
-Helps healing by clot dissolution

Question 20

Test for hemostasis:

Platelet disorders? ( 3)
Coagulation disorders? (6)

Answer 20

-tourniquet test
-bleeding time
-clot retraction

-clot retraction
-clotting time
-prothrombin time
-partial thromboplastin time
-thrombin time
-thromboplastin generation time

Question 21

Hemorragic disorders are ? (3)

Answer 21

-Platelet disorders
-Vascular disorders
-Coagulation disorders

Question 22

What are platelet disorders?

Answer 22

-Thrombocytopenic purpura (subcutaneous bleeding spots due to decrease in number of circulating platelets)

-von Willebrand’s disease ( impaired platelet adhesion along with defects in coagulation)

-Thrombasthenia ( defective platelet function )