Vascular Disorders & Thrombosis 2 Flashcards
Physiologic response at the site of blood vessel injury to seal the injured vessel and prevent blood loss
Normal hemostasis
What are the three general components involved in hemostasis?
Platelets, clotting factors, endothelium
Hemostasis mediated by platelets
Primary hemostasis
Hemostasis mediated by clotting factors
Secondary hemostasis
What are the two possible outcomes of failed hemostasis?
Blood loss (hemorrhage) or inappropriate clot formation (thrombosis)
What is the purpose of arteriolar vasoconstriction in the hemostasis process?
To reduce blood flow to the injured area
What is the purpose of “primary hemostasis” in the hemostasis process?
To form the primary hemostatic plug
How do platelets respond to the exposure of subendothelial von Willebrand factor (vWF)?
(5 steps)
Through adhesion, shape change, granule release, recruitment, and aggregation
What is done during primary hemostatic coagulation testing?
- Blood smear evaluation and platelet count
- Buccal mucosal bleeding time (to see how long it takes for primary clot to form)
What is the purpose of “secondary hemostasis” in the hemostasis process?
To deposit fibrin and form a secondary hemostatic plug
(mediated by: the coagulation cascade)
What process does secondary hemostasis follow?
(4 steps)
- Tissue factor (TF) release
- Coagulation factor activation (involving TF and platelet phospholipid)
- Thrombin activation
- Fibrin polymerization
Which pathway is associated with coagulation factor VII?
Extrinsic
Which pathway is associated with coagulation factors XII, XI, IX, and X?
Intrinsic
Which pathway is associated with coagulation factors X, V, II, and I (fibrinogen)?
Common
What are the (4) vitamin K-dependent coagulation factors assessed during coagulation assays (PT, aPTT)?
II, VII, IX, and X
Which anticoagulant substance is found in lavender-top blood tubes, and inhibits clotting by removing/chelating calcium from the blood?
Ethylenediaminetetraacetic acid (EDTA)
What is the purpose of “anti-thrombotic counter-regulation” in the hemostasis process?
To limit the size of the hemostatic plug
(mediated by: tissue plasminogen activator (t-PA) and thrombomodulin)
Describe what occurs during the fibrinolytic system.
Plasminogen is activated into plasmin by t-PA, and plasmin breaks fibrin down into fibrin degradation products (FDPs) or fibrin-derived D-dimers
Increased _____ indicates increased fibrinolysis - examples include disseminated intravascular coagulation (DIC) or blood clot formation
FDP
Degradation products of insoluble cross-linked fibrin that are more specific than FDPs as an indicator of blood clot formation and fibrinolysis - examples include DIC or recent thrombus formation
D-dimers
Which anticoagulant substance is found in light blue-top blood tubes, and inhibits clotting by chelating calcium and preventing the coagulation cascade?
Sodium citrate
Anticoagulant properties of the endothelium:
Thrombomodulin receptors bind thrombin, which activates the ______ C /______ S complex to inhibit factors Va and VIIIa.
(Same word for both spaces!)
Protein
Anticoagulant properties of the endothelium:
Heparin-like molecules activate ____________ ____, which inhibits thrombin and factors Xa and IXa.
Antithrombin III (also abbreviated to ATIII)
Anticoagulant properties of the endothelium:
Tissue factor pathway inhibitor (TFPI) inhibits factor ______.
VIIa
Procoagulant properties of the endothelium:
Injured endothelium releases ____ ____________ factor to stimulate platelet adhesion and ________ factor to promote thrombus formation.
Von Willebrand; tissue
Which anticoagulant substance is found in green-top blood tubes, and inhibits clotting by activating antithrombin?
Heparin
A type of “pinpoint” hemorrhage
Petechia
A type of hemorrhage that occurs in a focal, confined space
Hematoma
A type of hemorrhage where blood accumulates in the pericardial sac
Hemopericardium
A type of hemorrhage where blood accumulates in the peritoneal cavity
Hemoperitoneum
A type of hemorrhage where blood accumulates in the thoracic cavity
Hemothorax
