Hematology (Strauss) Flashcards
What are the 4 phases of blood clot formation?
- Vascular
- Platelet
- Coagulation
- Fibrinolytic
What is the phase of clot formation where blood vessels contract (collagen in the vessel contracts to stop the bleeding via a local myogenic spasm)?
Vascular phase
What is the phase of clot formation where platelets distort, clump, and stick to form initial platelet plug (will distort due to the action of instigators)?
Platelet phase
What is the phase of clot formation where blood profactors become factor and react to form fibrin (the basis for the clot)?
Coagulation phase
What is the basis for the blood clot?
Fibrin
What is the phase of clot formation where the clot dissolves to allow healing?
Fibrinolytic phase
What is the local autocoid that is released from traumatized tissue how long do they last, and where are they eliminated?
Synthesized in bone marrow by megakaryocytes
1-4 micrometers
7-10 day half-ife
Eliminated by macrophages in the spleen
Can platelets reproduce?
No. They have no nuclei.
Can platelets contract?
Yes. They have throbosethin, actin, and myosin, which are contractile proteins.
Why is a dental extraction the ultimate challenge to the patient’s ability to clot?
Can’t get primary closure.
Why are scaling and root planing potentially devastating if the patient can’t stop bleeding?
Can’t just easily stop the bleeding, plug it, close, etc.
The platelet surface is coated with what to keep them from adhering to normal endothelium but allows them to adhere to damaged cell walls?
Glycoprotein
Platelets have what on the membrane that activates multiple stages of the coagulation process?
- Phospholipids
2. Platelet Factor 3 (PF3)
Why is the half-life of a platelet and important consideration?
Factor in when taking patient off anticoagulation meds
What is released from platelets and endothelial cells to link the platelets with exposed collagen fibers?
Von Willibrand factor
How long until the initial platelet plug occur?
5-12 minutes
Is the platelet plug strong?
No, but it gives you initial stability
What can cause the fibrin clot to be formed?
- Damaged endothelium
2. Factors in the blood
How long does the fibrin clot take to form?
Up to 6-8 hours
How long with the fibrin clot (a scab) stay there?
A few days
Plasminogin becomes plasmin and dissolves what?
Fibrin clots. This is a process that is occurring all the time.
What is an irreversible platelet poison?
Aspirin
How long does the analgesia of aspirin last?
4 hours
For how long does aspirin irreversably poison your platelets?
7 days