Flashcards in B4 Thrombosis and Coagulation Deck (21):
What are platelets?
Irregularly shaped cells that don't have a nucleus
What are platelets derived from?
Megakaryocytes in the bone marrow
What is the life span of platelets?
5-9 days in circulation
What hormone is responsible for the regulation of platelet production?
What organs produce thrombopoeitin?
Liver and Kidney
What happens to old platelets?
They are destroyed by macrophages in the spleen and liver
What are the properties of platelet reserves?
Found in spleen
Released by splenic contraction
What is the first step in megakaryocyte differentiation?
True or false? Megakaryocytes can contain up to 32 copies of their DNA?
False - They can contain up to 64 copies
How do platelets form from megakaryocytes?
Cytoplasm budding off the membrane
What happens after all of the platelets have been made?
All that remains of the megakaryocyte is the cell nucleus.
What happens to the megakaryocyte remnants after platelet production?
The cell nucleus is destroyed by macrophages in the lung
How many platelets can be released from megakaryocytes?
What 3 granules do platelets contain?
What are the properties of dense granules?
Contain ADP/ ATP, Calcium and Serotonin
What is the function of dense granules?
Helps to stimulate aggregation
What is the main property of lambda granules?
Contain hydrolytic enzymes
What are the properties of alpha granules
Contain a bunch of clotting factors including:
Platelet factor 4
TGFB1 (Transforming growth factor B1)
PDGF (Platelet derived growth factor)
Coagulation factors V and XIII
What is thromboxane A2 responsible for?
Stimulates platelet production and aggregation
What is Thrombospondin- 1?