3.06 Hemostasis Flashcards
Lyses or dissolves the clot
Fibrinolytic system
First cellular evidence when there is a break in the endothelium to stop the bleeding
Platelet system
It is the reactive lining of the blood vessel
Basement membrane
Helps with platelet adhesion and aggregation and it releases tissue factor which plays a significant part in the clotting cascade
vWF
Down regulates thrombin formation and prostacyclin
Protein C
A potent vasodilator that resumes original blood flow; inhibits platelet aggregation in healthy vessels
Prostacyclin
The first response to an injury
Blood vessel contraction
For platelet adhesion, platelet should bind to the vWF through the ______ and to collagen through the _______
Gp1b receptor. Gp1a receptor.
Stimulates platelet aggregation. (2 factors)
ADP and Ca2+
Stimulates vascular spasms
Thromboxane A2
Clotting factor that do not usually participate in clotting in vivo
XII
At each stage, a precursor is converted to an activated protease in the presence of these two factors
Calcium and phospholipid factors
2 factors that must be present in the liver for this cascade to proceed to completion.
Calcium ions and Vitamin K.
Converts soluble fibrinogen into soluble fibrin
Thrombin
Factor that is responsible for the mesh formation of the clot
Factor XIII
Merger of the extrinsic and intrinsic pathways.
Common pathway
Which between the intrinsic and extrinsic pathway is the feedback loop?
Intrinsic pathway
Inhibits thrombin formation and Factor Xa. Absence of this results thromboembolism or thrombotic episodes.
Antithrombin
Inactivated factor Va and VIIa from resulting to the inhibition of the formation of a fibrin clot. Deficiency in these results to successive clotting.
Activated protein C and S.
Binds to thrombin and decreases its ability to produce fibrin
Thrombomodulin
Interrupt the hemostatic process on several levels
Calcium chelators (in vitro)
Affects post translational modulation (PTM) and give rise to dysfunctional factors that will prevent proper clot formation
Vitamin K antagonists (In vivo)
Inactivated thrombin and factor Xa. Neutralized by protamine. PT and aPTT prolonged.
Heparin
Vitamin K dependent factors
10, 9, 7, 2
Proceeds upon activation of plasmin.
Fibrinolysis
A clot in an unbroken vessel
Thrombus
A clot, air bubble, lipid droplet, or a thrombus moving through a vessel and possibly lodging anywhere i the vascular system
embolus
Anti coagulant (specifically vitamin K dependent factors)
Warfarin
Inhibits thrombin and factor Xa
Warfarin
Virchow’s Triad
V ascular trauma
I ncreased coagulability
R educed blood flow
T/F A negative family history (2-3generations) rules out inherited bleeding disorders.
False
Small pinpoint hematoma that is 1-2mm in diameter; generally caused by minor hemorrhage
Petechiae
A bruise about 1cm in diameter, generally round in shape; caused by bleeding under the skin
Purpura
> 3cm in size; commonly called a bruise
Ecchymoses
Deal seated collection of clotted blood in an organ, tissue, space or cavity; bleeding into cavities
Hematoma
Bleeding in a joint cavity
Hemarthrosis
Which of the following is an inherited vascular disorder? A. Senile Purpura B. Hemangioma C. Henoch-Schonlein Syndrome D. Scurvy
B.
Deficiency of platelets in the Blood.
Thrombocytopenia
Characterized by small and hypo chromic (paler than usual) red blood cell. leads to prolonged blood loss if left untreated.
Microcytic Anemia
Anemia characterized by normal MCV but hematocrit and hemoglobin levels decreased.
Normocytic Anemia
Normal platelet count
150-400 x10^9 per liter
Normal bleeding time
2-8minutes
aPTT measures what pathway?
Intrinsic pathway and common pathway
PT measures what?
Extrinsic pathway and Common pathway
Time required to form a clot when thrombin is added to the plasma is a measure of Fibrin formation.
Thrombin Time
Deficiencies associated with clinical bleeding.
Factors VIII, IX, XI
Substitute for bleeding time, stimulate primary hemostasis, superior to bleeding time.
PFA-100 Platelet Function Screen
