HEMOSTASIS PART II - N5315 ADVANCED PATHOPHYSIOLOGY,
HYPERSENSITIVITIES - N5315 ADVANCED PATHOPHYSIOLOGY,
ARACHIDONIC PATHWAY - N5315 ADVANCED PATHOPHYSIOLOGY,
SOLID ORGAN TRANSPLANT REJECTION - N5315 ADVANCED
PATHOPHYSIOLOGY, AIDS - N5315 ADVANCED P... EXAM QUESTIONS
AND ANSWERS
The coagulation cascade
What is the 2nd arm of hemostasis?
12
How many coagulation factors are there?
They are plasma proteins; most produced in the liver
What are the coagulation factors made of?
In order of discovery.
How are the coagulation factors named?
Zymogens
What are coagulation factors in an inactive form?
With a after factor roman numeral (ex. Va is activated factor V).
How is an activated zymogen noted as?
Extrinsic pathway
What is considered the primary pathway of coagulation?
,When Tissue Factor is exposed at the site of injury
When is the extrinsic pathway activated?
Tissue Factor (III) exposed; binds with VII to form TF/VIIa complex; TF/VIIa
activates X-Xa; Xa binds with Va and calcium to form prothrombinase complex;
prothrombinase complex converts factor II (prothrombin) to IIa (thrombin); IIa
then activates 4 factors (I - fibrinogen to Ia - fibrin; factors V, VIII and XIII); fibrin
(Ia) placed over platelet plug and XIIIa stabilizes the fibrin
What is the process of the extrinsic pathway?
No
Does a deficiency in factor XII (Hageman factor) cause bleeding?
To enhance the extrinsic pathway
What is the main function of the intrinsic pathway?
When the blood is exposed to negative charges which are found on the
molecules of ADP and ATP.
When is the intrinsic pathway activated?
Exposure activates XII (Hageman factor); XIIa then activates XI; XIa activates IX;
IXa then activates X; XA then forms the prothrombinase complex in the common
pathway
What is the process of the intrinsic pathway?
The process of carboxylation
What must vitamin K dependent coagulation factors undergo in order to be a functional
protein?
,Prior to the time a factor would be activated and is essentially part of the
maturation of the protein
When does carboxylation occur?
They will not be functional proteins and cannot participate in the coagulation
process.
What happens if vitamin K dependent coagulation factors do not undergo
carboxylation?
The change of glutamate to y-carboxygluatmate (which occurs after the
translation of glutamate) in the vitamin K dependent proteins involved in the
coagulation process.
What is carboxylation?
Factors II, VII, IX, X , protein C and protein S. Vitamin K is required as a co-factor
and works with the enzyme carboxylase to complete carboxylation.
What are the vitamin K dependent proteins?
It must be reduced by vitamin K oxide reductase
What must happen to Vitamin K in order for it to be used in carboxylation?
Warfarin
What drug inhibits vitamin K reduction?
It blocks the genetic coding for vitamin K oxide reductase thus decreasing the
amount available to reduce vitamin K; a lack of reduced vitamin K prevents the
process of carboxylation and decreases the amount of functional vitamin K
dependent coagulation factors; increases the risk of bleeding
How does warfarin work on the coagulation process?
, A deficient amount of coagulation factors and an increased risk of bleeding.
What does a vitamin K deficiency lead to?
a measure of the extrinsic pathway (tissue factor and FVII) and the common
pathway (factors II, V, X, I).
What is prothrombin time (PT)?
Vitamin K deficiency, liver diseases, deficiency of factors VII, II, V or fibrinogen,
and use of warfarin; primarily used to monitor warfarin therapy
When are prolonged PT values seen?
A measure of the intrinsic pathway (factors XII, XI, IX, VIII) and the common
pathway (factors II, V, X & I)
What is the aPTT?
Any deficiency or inhibitor of any coagulation factors except factor VII; primarily
used to monitor heparin therapy.
What can cause a prolonged aPTT?
Accelerates the rate at which antithrombin neutralizes thrombin and activated
factor Xa by 4000 fold
How does heparin work?
It binds with thrombomodulin which is a protein found on the endothelial cells;
this binding deactivates thrombin and leads to the activation of protein C;
activated protein C and protein S then go on to deactivate Va and VIIIa
What does thrombin do during clot formation?
HYPERSENSITIVITIES - N5315 ADVANCED PATHOPHYSIOLOGY,
ARACHIDONIC PATHWAY - N5315 ADVANCED PATHOPHYSIOLOGY,
SOLID ORGAN TRANSPLANT REJECTION - N5315 ADVANCED
PATHOPHYSIOLOGY, AIDS - N5315 ADVANCED P... EXAM QUESTIONS
AND ANSWERS
The coagulation cascade
What is the 2nd arm of hemostasis?
12
How many coagulation factors are there?
They are plasma proteins; most produced in the liver
What are the coagulation factors made of?
In order of discovery.
How are the coagulation factors named?
Zymogens
What are coagulation factors in an inactive form?
With a after factor roman numeral (ex. Va is activated factor V).
How is an activated zymogen noted as?
Extrinsic pathway
What is considered the primary pathway of coagulation?
,When Tissue Factor is exposed at the site of injury
When is the extrinsic pathway activated?
Tissue Factor (III) exposed; binds with VII to form TF/VIIa complex; TF/VIIa
activates X-Xa; Xa binds with Va and calcium to form prothrombinase complex;
prothrombinase complex converts factor II (prothrombin) to IIa (thrombin); IIa
then activates 4 factors (I - fibrinogen to Ia - fibrin; factors V, VIII and XIII); fibrin
(Ia) placed over platelet plug and XIIIa stabilizes the fibrin
What is the process of the extrinsic pathway?
No
Does a deficiency in factor XII (Hageman factor) cause bleeding?
To enhance the extrinsic pathway
What is the main function of the intrinsic pathway?
When the blood is exposed to negative charges which are found on the
molecules of ADP and ATP.
When is the intrinsic pathway activated?
Exposure activates XII (Hageman factor); XIIa then activates XI; XIa activates IX;
IXa then activates X; XA then forms the prothrombinase complex in the common
pathway
What is the process of the intrinsic pathway?
The process of carboxylation
What must vitamin K dependent coagulation factors undergo in order to be a functional
protein?
,Prior to the time a factor would be activated and is essentially part of the
maturation of the protein
When does carboxylation occur?
They will not be functional proteins and cannot participate in the coagulation
process.
What happens if vitamin K dependent coagulation factors do not undergo
carboxylation?
The change of glutamate to y-carboxygluatmate (which occurs after the
translation of glutamate) in the vitamin K dependent proteins involved in the
coagulation process.
What is carboxylation?
Factors II, VII, IX, X , protein C and protein S. Vitamin K is required as a co-factor
and works with the enzyme carboxylase to complete carboxylation.
What are the vitamin K dependent proteins?
It must be reduced by vitamin K oxide reductase
What must happen to Vitamin K in order for it to be used in carboxylation?
Warfarin
What drug inhibits vitamin K reduction?
It blocks the genetic coding for vitamin K oxide reductase thus decreasing the
amount available to reduce vitamin K; a lack of reduced vitamin K prevents the
process of carboxylation and decreases the amount of functional vitamin K
dependent coagulation factors; increases the risk of bleeding
How does warfarin work on the coagulation process?
, A deficient amount of coagulation factors and an increased risk of bleeding.
What does a vitamin K deficiency lead to?
a measure of the extrinsic pathway (tissue factor and FVII) and the common
pathway (factors II, V, X, I).
What is prothrombin time (PT)?
Vitamin K deficiency, liver diseases, deficiency of factors VII, II, V or fibrinogen,
and use of warfarin; primarily used to monitor warfarin therapy
When are prolonged PT values seen?
A measure of the intrinsic pathway (factors XII, XI, IX, VIII) and the common
pathway (factors II, V, X & I)
What is the aPTT?
Any deficiency or inhibitor of any coagulation factors except factor VII; primarily
used to monitor heparin therapy.
What can cause a prolonged aPTT?
Accelerates the rate at which antithrombin neutralizes thrombin and activated
factor Xa by 4000 fold
How does heparin work?
It binds with thrombomodulin which is a protein found on the endothelial cells;
this binding deactivates thrombin and leads to the activation of protein C;
activated protein C and protein S then go on to deactivate Va and VIIIa
What does thrombin do during clot formation?
