Normal Hemostasis Pursuit Flashcards
What inhibitor forms an irreversible complex with factors IIa, IXa, Xa, XIa, XIIa and
plasmin to slowly neutralize them
Antithrombin
What are the labile factors of the coagulation cascade and what gives them that name
V/VIII - short half lives
How is Tissue Plasminogen Activator (TPA) released?
APC causes it to be relased from endothelial cells
how is protein C activated?
thrombin-thrombomodulin complex
Bill and Joe stole some prescription drugs from their grandmother’s bathroom medicine
cabinet. Thinking the drug warfarin had a rocking name, they took a large dose at the
Slayer concert later that night. At the concert, a glass bottle was broken over Joe’s head
that caused severe lacerations which began bleeding profusely without any sign of
stopping. What could potentially counteract the warfarin and bleeding, at least
theoretically?
large doses of vitamin K, but it woudlnt work immediately
What is the only contact factor deficiency that causes bleeding?
XI
Bill was roughhousing with Joe and his arm was chopped off accidentally. Joe, being a
quick wit noticed a bottle of sodium citrate and remembering his hemostasis course
quickly dumped it on the wound. Was Joe a genius or a fool and why?
sodium citrate will bind calcium and act as an anticoag
When is it necessary to adjust the ratio of blood to anticoagulant and what type of
adjustment is needed?
when HCT is >55% less anticoag is needed
Low HCT more anticoag is needed
3 functions of plasmin
breakdown fibrin and fibrinogen
inactivate V/VIII
degrade XII
What is the substance needed to convert fibrinogen to fibrin and how does it work to
form a clot?
Thrombin cuts off fibrinopeptides A and B from the end of two polypeptide
chains. The remaining molecule is a fibrin monomer. These monomers will attach end
to end, polymerizing resulting in a fibrin clot
name two ways IX can be activated
XIa intrinsic / VIIa, TFIII and calcium (extrinsic)
What are the four components of the Intrinsic Tenase Complex?
VIII, IXa, calcium and PF3
What are the three components of the Extrinsic Tenase Complex?
TF3, VIIa, calcium
Name two roles of the thrombin-thrombomodulin complex
activate protein c and release TAFI
How does Tissue Factor Pathway Inhibitor work
inhibits extrinsic path VII/TIII complex
Plasmin can lyse both fibrin and fibrinogen; fibrinogenolysis is usually harder to achieve,
why?
antiplasmins will destroy most plasmin that escapes the clot
What are the six things activated by Factor IIa?
I, V, VIII, XIII, XI, Protein C
Which regulatory substance alters the fibrin clot thus inhibiting fibrinolysis?
Thrombin
Activatable Fibrinolytic Inhibitor (TAFI)
What mediates the activation of Factor VI
doesnt exist
Which normal inhibitor degrades factor Xa and Factor XI?
ZPI
Name the coagulation factor that plays a role in both the cascade and platelet
aggregation.
Fibrinogen (I)
What substance serves as a plasmin inhibitor only when Alpha2 anti-plasmin is
depleted?
alpha 2 macroglob
What substance is released from injured endothelial cells and activated platelets and
functions to neutralize TPA
PAI - 1 and 2 (1 is most important)
Name 7 substances that Factor II acts upon
I, V, VIII, XI, XIII, TAFI, Protein C
Name at least 2exogenous plasminogen activators
Tpa, Urokinase, streptokinase
How are Factor V and VIII affected if thrombin fails to act upon them?
slow but still work in the coag process
Thrombin enhances which coag factors?
V/VIII
A patient with a bleeding disorder was found to have the following screening test
results: PT-normal and APTT- prolonged. What are the possible factor deficiences?
XI, IX, VIII (bleeding)
What may happen to coagulation test results if the sodium citrate tube has a short
draw?
prolonged clot based tests, may neutralize calcium in the test reagent
Is Christmas magic?
IX is apart of the magic 4, yes
What are 3 shared traits among the magic 4 coagulation factors
vit K dependent
made in the liver
all depleated by oral anticoags
Which coagulation factor plays a role in clot formation as well as clot dissolution?
XII
