Fibrinolysis Flashcards
Final stage of coagulation, begins a few hours after fibrin polymerization and cross-linking
Fibrinolysis
Dissolution of clot by plasmin
Fibrinolysis
This is derived from plasminogen, which is produced by the liver
Plasmin
2 activators of fibrinolysis:
Tissue-type plasminogen activator (TPA) and Urokinase-type plasminogen activator (UPA)
They are released in response to inflammation and coagulation
TPA and UPA
Body’s defense against occlusion of blood vessels
Fibrinolysis
Remove minute clots from millions of tuny peripheral nerves
Fibrinolysis
Normally present in plasma, converted to plasmin by action of plasminogen activators
Plasminogen
A single-chain protein possessing five glycosylated loops
Kringles
Primary substance involved with the fibrinolytic system not normally found in circulation
Plasmin
Main proteolytic enzyme in fibrinolysis, also called fibrinolysin
Plasmin
Cleaves the fibrin clots, the product of coagulation
Plasmin
accomplished by the enzyme plasmin that digests the fibrin
strands of the clot as well as several clotting factors.
Plasminogen activator inhibitor 1 (PAI-1)
synthesized in the liver and is the primary inhibitor of free plasmin
a2-Antiplasmin (AP)
a serine protease inhibitor with the unique characteristic of both N- and C-terminal extensions.
a2-Antiplasmin
plasma procarboxypeptidase synthesized in the liver
that becomes activated by the
thrombin-thrombomodulin complex.
Thrombin-Activable Fibrinolysis Inhibitor (TAFI)
It inhibits fibrinolysis by cleaving exposedcarboxy-terminal lysine residues from partially degraded fibrin, thereby preventing the binding of TPA and plasminogen to fibrin and blocking the formation of plasmin
Thrombin-Activable Fibrinolysis Inhibitor (TAFI)
This system is activated by both the coagulation and
fibrinolytic systems
Kinin System
Kinin System Factors:
- Prekallikrein
- Kallikrein
- Kininogen
- Kinins
Principal inhibitor of coagulation
Anti-thrombin III (AT III)
Vitamin K dependent regulatory proteins:
Proteins C and S
Inhibit factor VIIa-tissue factor complex
Tissue factor pathway inhibitor
Inhibits thrombin, Xa, kallikrein, and plasmin
Alpha-2 macroglobulin
Inhibits XIa and inactivates plasmin
Alpha-1 Antitrypsin
Inhibits C1 from the complement cascade and XIIa, XIa, kallikrein and plasmin
C1 Inhibitor
Prevention of blood loss
Hemostasis
Step of Hemostasis:
- Vasoconstriction
- Temporary Platelet Plug/ Primary Hemostasis
- Coagulation/Secondary Hemostasis
- Fibrinolysis
- Regeneration of cells
End result of Primary Hemostasis:
Platelet Plug Formation
Extrinsic Pathway is tested/measured by:
Prothrombin Time
Extrinsic factor is activated by:
Tissue factor
Extrinsic pathway inhibitor:
Warfarin
Intrinsic pathway is tested/measured by:
PTT/aPTT
Intrinsic pathway is activated by:
Subendothelial collagen
Intrinsic pathway inhibitor:
Heparin
Common pathway is activated by:
Extrinsic and Intrinsic Pathway
Common pathway is tested by:
PT/APTT
Primary hemostasis tests:
Platelet count, Bleeding time, Platelet aggregometry
