patho ch. 21 and 22 book notes Flashcards
(52 cards)
three stages of hemostasis
- vascular constriction
- formation of platelet plug
- blood coagulation
in response to vessel injury, smooth muscle contraction (vasospasm) reduces blood flow
vascular constriction
vascular constriction is mediated by factors like
thromboxane A2 and endothelelin-1
Platelets adhere to exposed collagen via von Willebrand factor (vWF), become activated, and aggregate to form a temporary plug
formation of platelet plug
platelets can adhere to exposed collaged via… to form a plug
vWF
A cascade of clotting factors leads to the conversion of fibrinogen to fibrin, stabilizing the platelet plug into a firm clot
blood coagulation
stabilizes the platelet plug to form a firm clot
fibrinogen to fibrin
Occurs 20–60 minutes post-clot formation; platelets contract, pulling fibrin threads together, consolidating the clot, and bringing wound edges closer
clot retraction
Plasminogen is activated to plasmin, which digests fibrin, dissolving the clot and restoring normal blood flow.
clot dissolution (fibrinolysis)
clot retraction occurs how many minutes post clot formation
20-60
digests fibrin to dissolve clot
plasmin
abnormal clotting includes what 2 things
thrombosis and bleeding disorders
causes of increased platelet function
Conditions like thrombocytosis, inflammation, or myeloproliferative disorder
effects of increased platelet function
thrombotic effects like strokes or heart attacks
disorder that increases clotting activity. genetic leading to resistance against activated protein C
factor 5 leiden mutation
disorder that increases clotting activity. autoimmune condition where antibodies increase the clot formation
antiphospholipid syndrome
manifestations of thrombocytopenia
easy bruising, petichiae, prolonged bleeding from cuts, spontaneous bleeding from gums or nose, and blood in urine or stools
Factor VIII deficiency; X-linked recessive inheritance
hemophilia A
Factor IX deficiency; X-linked recessive inheritance
hemophilia B
in hemophilia A, factor 8 impairs what and leads to
impairs the intrinsic pathway of clotting and leads to deep tissue bleeding
in von willebrand disease, deficiency or dysfunction of vWF affects what and leads to
platelet adhesion and factor 8 stability and leads to musculocutaneous bleeding
is characterized by widespread activation of the coagulation cascade, leading to the formation of microthrombi throughout the vasculature. This consumes clotting factors and platelets, resulting in severe bleeding and potential organ failure.
disseminated intravascular coagulation
plasma makes up what percent of blood
55%
water makes up what percent of plasma
90%
