BLOOD 5 Flashcards
What are platelets needed for?
What does thrombopoietin do?
Platelet half-life
Blood clotting
Increases platelet numbers
10 days
Three phases of hemostasis
1) Vascular phase
2) Platelet phase
3) Coagulation phase
Vascular phase
Vasoconstriction prolonged by?
Neurogenic and myogenic control
Serotonin, Endothelin-1, Thromoboxane A2
Platelet phase
1) Exposed collagen: binds and activated platelets
2) Factors released from platelet
3) Factors attract more platelets
4) Platelets aggregate from plug
Platelet Phase?
Where the von Willebrand factor made?
What does it bind to?
What effect does it have?
Endothelial cells and platelets
Binds to both collagen and platelets
Causes aggregation of platelets
Factors that cause platelet aggregation
ADP
paf
Serotonin
Thromboxane a2
What does platelet aggregation lead to
Vasoconstriction
Platelet activation
Helps adhesion
What the role of Prostacyclin (prostagladin I2, PG12 and nitiric oxide (NO).
Prevent platelet adhesion and are vasodilators
What is prostacyclin
anti-coagulant
Arachidonic acid leads to PGH2 synthesis: produces three chemicals?
1) Prostaglandins
2) Thromboxane A2
3) Prostacyclin
Cyclooxygenase?
Aspirin?
Causes synthesis
Inhibits thromboxane A2
Coagulation cascade common pathway:
1) Factor X
2) Prothrombin
3) Fibrinogen
4) Factor XIII
1) Active X
2) Thrombin
3) Fibrin
4) Active XIII
What is the final product of the coagulation cascade?
What cofactor is required for blood clotting?
Cross-linked fibrin polymer
Ca+
Where is the Extrinsic Pathway found
Responds to ?
Name the 4 tissue factors involved?
Which factor causes (+) feedback
Found in tissues
Cell injury
Factor VII, Factor III, Factor IX and X
Active factor X
What Intrinsic pathway respond to?
Which factors are activated?
Factor XI is activated by?
Contant activation
Factors: XII, XI, IX
Thrombin positive feedback from common pathway of thrombin
Which factor does the von willebrand factor regulate
Why is vitamin K required?
What is Cuomadin (Warfarin) and what its function?
Levels of VIIII
Synthesis of thrombin, VII, IX and X
Anticoagulant which blocks the action of vitamin K
One effect of a deficiency in factor IX and factor VIII?
Severe bleeding
Cell based: location
Initiation phase
What starts this phase?
Cell membrane of smooth muscle?
Exposure of tissue factor: starts to produce small amounts of thrombin
Amplification phase
Which factors does thrombin activate?
Factors V, XI and VIII
Propagation phase
Active factors on the surface of platelets form ?
What is a thrombin burst?
Tenase
When prothrombin cleaves large amount of prothrombinase result in large amounts of thrombin
Three characteristics of von Willebrand disease
1) Most common coagulation disorder
2) Problems in quality or quanitity of von willebrand factor
3) Areas with high number of smlal capillaries (skin, gi tract, uterus)
Causes of Hemophilia A
Causes of Hemophilia B
Factor VIII
Factor IX
How is the clot removed after healing has taken place?
What is this process called?
Requires thrombin, plasminogen and tPA to form plasmin: which cleaves the fibrin polymer to firbin fragments
Firbinolysis
Where is tPA released?
Thrombus?
Embolus?
Slowly by the endothelium
Blood clot attached to vessel wall
Floating blood clot
Physiological anticoagulants: released from:
1) Plasminogen/Plasmin
2) Tissues plasminogen activator (tPA)
3) Antithrombin III
4) Prostacyclin
1) Liver
2) Mant tissues
3) Liver
4) Endothelial cells
Physiological anticoagulants: activated by:
1) Plasminogen/Plasmin
2) Tissues plasminogen activator (tPA)
3) Antithrombin III
4) Prostacyclin
1) tPA and thrombin
2) Normally present
3) Heparin
4) N/A
Physiological anticoagulants function:
1) Plasminogen/Plasmin
2) Tissues plasminogen activator (tPA)
3) Antithrombin III
4) Prostacyclin
1) Breaksdown fibrin
2) Activates plasminogen
3) Blocks IX,X, XI,XIII, thrombin
4) Inhibits platelet aggregation
