Hemostasis, Platelet, Coagulation, Anti-coagulant Drugs (Exam 3) Flashcards
What is hemostasis?
arrest of bleeding by the vasoconstriction and coagulation
What are the 3 functions of platelets?
platelet adhesion | release reaction | platelet aggregation
Describe platelet adhesion function of the platelet?
after vessel injury = platelets adhere to sub-endothelial connective tissues
What is platelet adhesion dependent on?
the presence of factor 8 (VIII) = von-Willebrand factor
What are the 3 molecules found in the granules of platelets?
ADP, thromboxane A2, serotonin
Describe the release reaction function of platelets?
platelet exposed to collagen = release granule contents
Describe the platelet aggregation function of the platelet?
ADP and ThromboxaneA2 release = additional platelets aggregate to injury site = platelets swell = platelets adhere together = aggregation = factor 3 exposed for coagulation protein complex formation
What is the role of ADP?
attracts more platelets to the site
What is the role of serotonin?
promotes vasoconstriction
What is the role of Thromboxane A2?
promotes platelet aggregation, degranulation, and vasoconstriction
Why is vasoconstriction important in blood coagulation?
slow blood flow to injury site to plug the hole
What is the protein factor that initiates the coagulation process at the injury site?
factor III (factor 3) = platelet thromboplastic factor 3
What is the protein factor that acts as the connecting piece for all of the processes carried out in coagulation?
factor XIII (factor 13)
What is blood coagulation?
the process of forming a clot
What is the result of blood coagulation?
platelets aggregate at site of clot | fibrin ties up platelets to form clot
What are the 3 pathways involved in blood coagulation?
intrinsic activation, extrinsic activation, common pathway
What is the end product of the Intrinsic Activation Pathway?
Factor IXa (factor 9a)
What is the end product of the Extrinsic Activation Pathway?
Factor VIIa (factor 7a)
What are the protein factors and mineral needed to create protein factor Xa (factor 10a)?
7a + 9a + Ca2+ = 10a
What is the end product of the common pathway?
thrombin
What is the role of factor XIIIa (factor 13a)?
converts fibrin into stable form by making covalent bonds
How is fibrin made? What are the factors needed?
thrombin drives fibrinogen (with Ca2+) = fibrin
What will happen if one of the protein factors are missing from the blood coagulation process?
cause a disease (specific to which factor is missing)
What is the treatment for missing coagulation protein factors?
blood transfusions
What are the 4 ways coagulation is controlled?
factor concentration-dependent | liver | anti-thrombin | plasmin
What is significant about factor concentration dependence in order to control coagulation?
concentration of protein factors need to be high enough to initiate the hemostasis process
How does the liver control coagulation?
destroy unused factors in parenchymal cells
What is the role of anti-thrombin? What activates it?
inactivates thrombin | heparin activates anti-thrombin
What does plasmin do?
digests fibrin, fibrinogen, factors V and VIII (factors 5 and 8)
What is the number one observation on people who suffer from coagulation factor deficiency?
hematoma on thigh due to prolonged-sitting
What are the 3 lab screening tests used in diagnosing coagulation disorders?
prothrombin time (PT) | activated partial thromboplastic time (APTT) | thrombin time (TT)
What is the function of the prothrombin time (PT) screen test?
tests extrinsic and common pathways
What is the function of the activated partial thromboplastic time (APTT) screen test?
tests intrinsic and common pathways
What is the function of thrombin time (TT) screen test?
tests fibrinogen to fibrin conversion
What is Hereditary Hemorrhagic Telangiectasis (HHT)?
vascular and platelet genetic autosomal dominant trait disorder
What are the symptoms of Hereditary Hemorrhagic Telangiectasis (HHT)?
abnormal blood vessel formation | skin lesions | a lot of nose bleeds
What reduces coagulation in Hereditary Hemorrhagic Telangiectasis (HHT)?
asprin
What are the 3 causes of thrombocytopenia?
failure platelet production | increased destruction of platelets | abnormal distribution of platelets at unnecessary sites
What is Hemophilia A?
most common coagulation disorder | genetic, found on X-chromosome (sex-linked)
What is Hemophilia A due to?
absence or low level of factor VIII:C (factor 8) procoagulant activity clotting activity
Who are most affected by Hemophilia A? Who are the carriers of Hemophilia A?
men | women = carriers
What is the characteristic of Hemophilia A?
factor VIII:C (factor 8) procoagulant activity deficiency
Where are the main sites of hemorrhage for Hemophilia A?
muscle, joints, post-trauma or surgery
What is the most serious complication for Hemophilia A?
antibodies against factor VIII (factor 8)
What is the treatment of Hemophilia A?
factor VIII (C-antigen) and desmopressin = increase plasma factor VIII (factor 8) production
What is Hemophilia B?
Similar clinical features as Hemophilia A just with factor IX (factor 9)
What is another name for Hemophilia B?
Christmas Disease
What is the characteristic of Hemophilia B?
factor IX (factor 9) deficiency
What is the treatment of Hemophilia B?
factor IX (factor 9) concentrates
What is von-Willebrands disease?
SAME as Hemophilia A BUT different = deficient levels if factor VIIIR:AG (factor 8) related antigen
What is disseminated intravascular coagulation (DIC)?
coagulation happens everywhere in body = exhaust all of available coagulation factors
What are the 2 causes of disseminated intravascular coagulation (DIC)?
entry of pro-coagulant material from: transfusion, snakebites, premature separation of placenta | widespread endothelial damage and collagen exposure (septecemia, viral infection)
What is the treatment for disseminated intravascular coagulation (DIC)?
fresh frozen plasma | supportive fibrinogen and platelet
What are the 2 anti-coagulant drugs discussed? Which one is the most commonly used one?
heparin (most common) | coumarin (warfarin)
How is heparin administered and what is its half-life?
intravenously | ~1 hour
Where was coumarin first found?
in cattle
What is the function of coumarin?
(anti-vitamin K) decreases activity of anti-vitamin-K dependent factors 2, 7, 9, 10 (factors II, VII, IX, X)
How is coumarin administered?
orally