Hemostasis - Midterm Wrapup Flashcards
What is Hemostasis?
Balance b/t Bleeding & Clotting
What’s involved in the Process of Hemostasis?
Vessel Wall
Platelets
Coag. Cascade
Fibrinolytic System
What are the different layers of Arteries & Veins?
Tunica Adventitia
Tunica Media
Tunica Intima
What are Capillaries made of?
Single Endothelial Layer
Which Endothelial layer forms a barrier b/t fluid within the blood vessel & thrombogenic material in the Tunica Media?
Tunica Intima - Endothelial Layer
Which factors are considered Procoagulants?
Von Willebrand Factor (vWF) - how platelets stick to subendothelium
&
Tissue Factor - Activates clotting cascade during injury
&
Vitamin K (Nonherbal Dietary)
Which Endothelial Factors cause Vasoconstriction?
Thromboxane A2
ADP
Serotonin
Which Endothelial Cells cause Vasodilation?
Nitric Oxide
&
Prostacyclin
Which Endothelial Layer is Thrombogenic, Active, and contains Collagen & Fibronectin?
Tunica Media - Subendothelial
What is the function of the Tunica Adventitia?
Controls blood flow by Vasodilation via Nitric Oxide & Prostacyclin
What are the Mediators in the Endothelial Layer or Tunica Intima?
vWF
Tissue Factor
Prostacyclin
Nitric Oxide
______ are round, disk-like, and are formed in the Bone Marrow.
Platelets - important part of clotting response - homeostasis impossible w/o them
What does the Platelet Cell contain?
Mitochondria
Glycogen Stores
Proteins
Calcium
Enzymes
Alpha Granules
Dense Granules
Which factors are part of the Platelet’s Alpha Granules?
vWF
Fibrinogen
Fibronectin
Platelet Factor 4
Platelet Growth Factor
What are considered part of the Platelet’s Dense Granules?
Serotonin
ADP
ATP
Histamine
Epinephrine
Platelets produce ______, which activate coag factors & influences platelet recruitment
Platelets produce thrombin, which activate coag factors & influences platelet recruitment
Platelets only activated & active w/ tissue trauma
True/False: Platelet contain a Nucleus & DNA, but no RNA.
False - Platelets have no nucleus, RNA, or DNA
What is involved in the Formation of a Plug for Vessel Injury?
Adhesion
Activation
Aggregation
What happens when there is a Disruption of Endothelial Lining?
Autonomic Vessel Contraction w/ Thromboxane A2 & ADP
How does Adhesion work when Forming a Plug?
- vWF moves to Endothelial Lining
- Glycoprotein Ib (GpIb) Receptors emerge from Platelets
- GpIB attaches to vWF, attracting more platelets & making them sticky
How does Activation happen in the Formation of a Plug?
Tissue factors activate Platelets & 2 more Glyycoproteins (IIb & IIIa) emerge from platelets
What is the name of the Cell Feet that shows in Activated Platelets?
Pseudopodia
How does Aggregation happen w/ the formation of a plug?
Gp IIb & Gp IIIa sticks platelets together to Seal & Heal injured site
&
Platelets release Alpha, Dense, and Contractile Granules, Thrombin, & Procoags
What activates Cofactors/Zymogens?
Tissue/Organ Damage
Normally circulates in an Inactive State until Activated
Cofactors in the Clotting Cascade are enzymes w/ the exception of Factor ___ & Factor ___.
Cofactors in the Clotting Cascade are enzymes w/ the exception of Factor V & Factor VIII
What is Factor I?
Fibrinogen from the Liver that forms clot w/ No Vit. K Dependency
What is Factor II?
Prothrombin from the Liver w/ Vit. K Dependency.
What is Factor III?
Tissue Factor/Thromboplastin from the Vascular wall & cell membranes.
Factor VII Cofactor
What is Factor IV?
Calcium from Diet that promotes clotting reactions
What is Factor V?
Proaccelerin from the Liver that forms a Prothrombinase Complex
Factor X Cofactor
What is Factor VII?
Proconvertin from the Liver w/ Vit. K Dependency
What is Factor VIII?
Antihemophiliac from the Liver w/ No Vit. K Dependency
Factor IX Cofactor
What is Factor IX?
Christmas Thromboplastin from the Liver w/ Vit. K Dependency
What is Factor X?
Stuart from the Liver that Forms Prothrombinase Complex w/ Factor V and is Vit. K Dependent
What is Factor XII?
Hageman from the Liver w/o Vit. K. Dependency
What is Factor XIII?
Fibrin Stabilizer from the Liver that Crosslinks Fibrin w/o Vit. K
Which factor is known as Fletcher & Activates Factor XII and Cleaves HMWK
Prekallikrein
What Activates the Extrinsic /Tissue Factor Pathway?
Crushing Injury or Organ Trauma Outside the Vessel Wall
What activates the Intrinsic / Contact Activation Pathway?
Damage to Actual Blood Vessel
Initated by Prekallikrein & HMWK
Which Factors are involved in the Intrinsic / Contact Activation Pathway?
Factors 8, 9, 11, 12
How does the Common Pathway Work?
- Factor X (Stuart) + Factor V(Proaccelerin) = Factor XV (Prothrombinase Complex)
- Factor II (Prothrombin) –> Factor IIa (Thrombin)
- Factor I (Fibrinogen) –> Factor Ia (Fibrin)
- Factor XIII Activation (Fibrin Stabilizing)
- All amounts to a stable clot
There are the Intrinsic, Extrinisic, and Common Pathways. Which pathway is considered the Terminal pathway?
Common Pathway
As the secondary plug leaves, it heals the vessel by weaving the edges together
Why is the Conversion of Prothrombin to Thrombin essential?
Thrombin recruits Platelets & is necessary for Fibrin to form a stable clot
How does Thrombin act as an Anticoagulant
Prevents Runaway Clots by Releasing tPA
Stimulates Proteins C & S
Works w/ Antithrombin III to stop coagulation
Which Mineral is involved in many parts of the Common Pathway?
Calcium
What are the 3 Stages of Cell Based Coagulation
- Initiation
- Amplication
- Propagation
What happens in Cell Based Coagulation Amplication?
More Thrombin
More Factor 9 on Platelet Surface
vWF promotes Aggregation
What happens in Cell Based Coagulation Propogation?
All Factors work together to finally Activate Prothrombin making A LOT of Thrombin, which then promotes Fibrinogen to Fibrin making a secondary plug
What is the First Step of the Fibrinolytic System?
Increase Blood Flow to Injured Site
&
Remove Procoags, ADP & Thromboxane from vessel
What does Antithrombin III do?
Removes factors from the Clotting Cascade to Disrupt Clotting
What controls the Fibronolysis Process?
Plasma Proteins
What is Plasminogen?
Liver enzyme that is activated and converted to Plasmin by tPA & Urokinase
What does Plasmin do?
Degrades Fibrin
What stops the Fibrinolysis Process when the Clot is Digested?
Alpha-Antiplasmin & tPA Inhibitor
What are some Antiplatelets?
NSAIDs
Persantine
Plavix
Ticlid
What are some Antifibrinolytics?
Amicar & Tranxemic Acid
What are some Nonherbals that Affect Coagulation?
Vit. E
Vit. K
CoQ 10
Zinc
Omega 3 Fatty Acids
What Herbal Medications can increase Bleed?
Ginko
Garlic
Ginger
Feverfew
What is the Normal Prothrombin Time?
12 - 14 seconds
Altered by Coumadin
What is the Normal ACT?
80 - 150 seconds
What is the Normal Fibrinogen Levels?
> 150 mg/dL or 200 - 350 mg/mL
What is the Normal D-Dimer?
< 500 mg/mL
What are normal Fibrinogen Degradation Product Levels?
< 10 mcg/mL
What determines Bleeding Time?
Microvascular Contraction & Platelet Function
What is considered Thrombocytopenia?
Platelets < 100k
< 50k = bleed
< 20k = spont. bleed
Which Pathways are associated with PT/INR?
Extrinsic & Common Pathways
Which Pathways are associated w/ PTT?
Intrinsic & Common Pathways
When should Platelets be given?
Low Risk Sx: <20k
Average Risk Sx: < 50k
CNS Sx: < 100k
When should FFP be given?
Unable to obtain Pt/INR/PTT
Urgent Warfarin Reversal
Factor Deficiencies
When should Cryoprecipitate be given?
Fibrinogen deficiency
What is the most common Inherited Coagulation Disease?
Von Willebrand Disease
What causes bleeding in Hemophilia?
Incomplete Clot
What is DIC?
Thrombocytopenia & Depletion of Clotting Factors
How is DIC treated?
Underlying Cause
Heparin
Supportive Therapy
Blood Products
What is the Difference b/t Type I & II Heparin-Induced Thrombocytopenia?
Type I
Non-Immune Mediated from High Dose Heparin w/ a 1-4 day onset
Type II
Immune-Mediated from Low Dose Heparin w/ a 5 - 14 day onset
More Serious & Severe
