Hemostasis Flashcards
What is hemostasis?
The body’s natural process of stopping bleeding from a damaged blood vessel
What are the 3 steps for hemostasis?
- Vascular spasm
- Plug formation
- Coagulation
What does vascular spasm mean?
Blood vessel tightens = less blood travels
What is plug formation?
The process of forming a temporary plug to seal a damaged blood vessel and stop bleeding
What does vasoconstriction mean?
The narrowing (constriction) of blood vessels by small muscles in their walls
What helps plug formation?
Platelets
What do platelets do that help plugging?
Release chemicals that make nearby platelets sticky
What does Von Willebrand factor do?
Helps platelets stick together to form clots and stop bleeding
What does serotonin do?
Enhance vascular spasm
What does ADP do?
Causes more platelets to stick together
What does thromboxane A2 do?
Does both (increase vascular spasm and aggregation)
What does prostaglandin do?
“Don’t come here” ???
What is the purpose of a vascular spasm?
Buys time so the clot has time to seal
Which is slower, intrinsic or extrinsic?
Intrinsic (mins)
How many clotting factors are there?
13
What is coagulation?
Creates a “mesh” that forms a clot
What is this intrinsic pathway?
The factors needed for clotting are present in the blood
What is extrinsic pathway?
The factors needed for clotting are present outside of the blood
Both intrinsic and extrinsic lead to which factor?
X and thrombin
Factor X produces what 2 factor names?
Thromin and eventually fibrin
What is the inactive factor of fibrin called?
Fibrogen
What do you have to do to activate a factor?
Cleave/break off part of the molecule
What is the inactive factor of thrombin called?
Prothrombin
The order of the factors are the order they were ___________
discovered
What factor of X comes first?
Prothrombin (thrombin)
A lot of factors are made in the:
liver
What does fibrin do?
Form webs that trap everything (blood)
What does factor XIII do?
Strengthens and tightens the web
Clot retraction has ____ and _____ to contract the clot
actin and myosin
As the platelets contract, it squeezes out:
serum
What is PDGF (platelet-derived growth factor)?
Released by platelets
Helps rebuild the vessel wall (helps healing)
What does fibrinolysis do?
Removes unneeded clots when healing has occured
What does plasmin do?
Produces plasmin
The bomb in the middle of the clot
What does plasminogen do?
Produces plasmin (from inactive to activated)
What does tissue plasminogen activator do?
Produces plasminogen
_____ vessels inhibit clots
Large
What does antithrombin III do?
Inactivates thrombin not bound to fibrin
What does heparin do?
Increases the activity of antithrombin III
What is thromboembolytic disorder?
Condition that causes undesirable clot formation
What is disseminated intravascular coagulation (DIC)?
Widespread clotting and severe bleeding
What is thrombocytopenia?
Not enough platelets
What is hemophilia?
Hereditary bleeding disorders
Hemophilia A is missing factor:
VIII
What are the 3 hemophiliacs?
A, B and C
Hemophilia B is missing factor:
IX
Hemophilia C is missing factor:
XI
