Thrombocytes Flashcards
What is the function to thrombocytes?
Absorb and carry plasma factors required for formation of fibrin and contributes to hemostasis
What does a thrombosite look like?
Non-Nucleated, variable size, pale blue with purple/pink granules, tend to be sticky
What is a megakaryocyte?
Largest cell in bone marrow
How are thrombocytes formed?
In red bone marrow, are fragments of megakaryocyte
How many platelets do canines have?
200,000-500,000/ul
How many platelets do cats have?
300,000-800,000/ul
How many platelts do horses have?
800,000-300,000/ul
How many platelets are needed to make a clot?
50,000/ul
What is hemostasis?
Arrest of bleeding or circulation
When is hemostasis initiated?
When vascular injury disrupts blood vessels exposing surrounding tissue to flowing blood
What is chemo taxis?
Use of chemicals to attract or repel something
What are three things that work together to stop bleeding?
Blood vessels, platelets, clotting factors
What is collagen?
Insoluble protein found in connective tissue
What makes a platelet plug in an injured vessel?
Platelets adhere to outside tissue and release chemicals that cause platelet surfaces to become sticky and collect more platelets and also release substances for Vaal constriction
What are extrinsic factors?
Ingredients found outside the vessels
What are thromboplstins?
They accelerate the clotting mechanisms
What are intrinsic factors?
All components necessary for clotting are present in normal blood but are slow.
What are two extrinsic factors?
Collagen and thromboplastins
What are two intrinsic factors?
Clotting factors and platelets
Explain the cascade of coagulation
Extrinsic factors: collagen, and thromboplastkns to accelerate the process.
Intrinsic factors: prothrombin will creat thrombin, fibrinogen will combine with thrombin and creat fibrin wich will join with platelets to creat the clot
How do the clots retract?
Fibrin mesh work will shrink and become more dense and stronger and push serum out.
Explain clot dissolution
Enzyme plasmin (fibrinolysin) is activated by damaged tissues and thrombin from inactivated form plasminogen. Plasmin is breaks down clot after a few days to build up
What are two substances that can prevent clots?
Heparin and plasmin
What prevents platelets from adhering?
Smooth lining of vessels
What are intravascular clots?
Clots that occasionally occur within the vasculature system
What is thrombus?
A clot that adheres to a vessel wall
What can a thrombus do?
Can block blood supply to the heart and cause heart damage
What is an embolus?
Intravascular clot floating in the blood and can be lodged in small vessels blocking blood flow and causing damage
