Hemostasis Flashcards
() is a fast series of reactions for stoppage of bleeding
-requires () factors and substance released by platelets and injured tissues
hemostasis
clotting
Three steps involved:
hint: VPC
vascular spasm
Platelet plug formation
coagulation( blood clotting)
Sep 1: () spasm
-Responds to injury with vasoconstriction
-Triggered by
- direct injury
-Chemicals released by endothelial cells and platelets
-Pain reflexes
-Natural ()
vascular
tourniquet
Step 2: () Plug formation
-Platelets stick to () fibers that are exposed when vessel is damaged
-When activated platelets swell, become () and () and release ()
-are fine for small vessel tears
collagen
spiked
sticky
chemical messengers
Step 3: ()
blood clotting reinforces platelet plug with fibrin threads
occurs in 3 phases
coagulation
Coagulation:
step 1:() activator formed
Step 2: () converted to active enzyme()
Step 3:() converts soluble ( to )
-fibrin causes plasma to become a gel like trap catching formed elements
prothrombin
thrombin
fibrinogen to fibrin
Coagulation:
() pathway- clotting factors () the blood
-() damage
() pathway- located () blood
-Triggered by exposure to () also called factor 3
-involves physical trauma to vessels
intrinsic
endothelial
Extrinsic
tissue factor
() retraction:
-Draws ruptured blood vessel edges together
-Smooth muscle cells and fibroblast rebuild blood vessel wall
-() lining restored
Clot
Endothelial
Clot retraction and ()
-Clots are removed after repair is completed
() plasma protein that is trapped in clot converted to () a fibrin-digesting enzyeme
Fibrinolysis
Plasminogen
Plasmin
(): factor xii(12) and thrombin all play a role in conversion process
Tissue plasminogen activator
tPA is used in hosptials in the case of stokes () heart attacks () and Pulmonary emboli (PE)
CVA
MI
