Term
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Definition
defense mechanism designed to control bleeding and conserve blood volume.
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Term
Hemostasis requires the interaction between which 3 elements? |
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Definition
(1) platelets, (2) plasma coagulation factors, (3) blood vessels.
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Term
What is primary hemostasis |
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Definition
involves accumulation and aggregation of platelets in an injured vessel to form a "plug" to slow down the loss of blood.
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Term
What is normal bleeding time |
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Definition
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Term
What is the duke bleeding time method |
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Definition
fatty portion of earlobe
normal 1-3 minutes; borderline: 3-6 minutes
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Term
What is the IVY bleeding time method |
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Definition
dry surface of forearm using a constant pressure
template standard 3mm depth & length
touch filter paper to droplet every 30 seconds
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Term
What is the Meilke method |
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Definition
forearm
wound is 9 mm (length) x 1 mm (depth)
avoids venules, cuts capillary
touch droplet with filter paper every 30 seconds
normal 3-10 minutes
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Term
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Definition
after the blood sample is incubated with exogenous reagents, the time of clot formation is measured.
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Term
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Definition
after the blood sample is incubated with exogenous reagents, the time of clot formation is measured.
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Term
What does Anticoagulant: sodium citrate do
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Definition
action: binds ionized calcium
preserves labile factors V and VIII
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Term
How would PT be affected if the ratio of blood to anyicoagulant was off |
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Definition
unbound citrate prolongs PT and APTT
Citrate binds to Ca++ reagent and decreases Ca++
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Term
What is the normal range for PT |
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Definition
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Term
What reagents are used in PT |
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Definition
thromboplastin: tissue factor
calcium chloride: source of Ca++ ions
buffer: stabilizes pH
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Term
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Definition
plasma (source of prothrombin or Factor II and Factors VII, V, X, and I)
complex between tissue factor (thromboplastin) with Factor VII, activates Factor VII
TF and VIIa and platelet phospholipid and calcium activate Factors IX and X
Xa complexes with Va (also platelet phospholipid and calcium) and converts prothrombin to thrombin
thrombin converts fibrinogen to fibrin
clot formation is detected visually or by optical or electromechanical sensors
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Term
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Definition
When clot is formed electrical contact with stationary probe is maintained and timer shuts off
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Term
What does prolonged PT indicate? |
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Definition
most sensitive to - factor VII def.
Moderatly sensitive to - factor V and X def.
and severe fibrinogen and prothrombin def
NOT SENSITIVE TO Factor VII and IX def |
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