platelets

Question 1

primary hemostasis

Answer 1

initial hemostasis involving activation of platelets and formation of platelet plug

Question 2

clinical sxs associated with primary hemostatic defect

Answer 2

petechia

ecchymoses

bleeding from mucosal sites (gingival bleeding, hematuria, epitaxis, GI bleeding)

prolonged bleeding from injection sites

Question 3

secondary hemostasis

Answer 3

hemostasis involving the coagulation cascade and formation of fibrin clot

Question 4

clinical sxs associated with secondary hemostatic defects

Answer 4

hematomas

bleeding into joints

bleeding into body cavities

bleeding into muscle

Question 5

Thrombopoietin (TPO)

Answer 5

primary stimulus for platelet pdn

constantly being produced in mainly the liver (also renal tubular epithelium and bone marrow stromal cells)

cleared from circulation by platelets and megakaryocytes

we dont see thrombocytopenia due to decreased TPO in animals with liver failure

Question 6

what is the lifespan of a platelet?

Answer 6

6 days

Question 7

What influences the blood platelet concentration

Answer 7

production

consumption

destruction

redistribtuion

Question 8

what receptors are on the surface of platelets?

Answer 8

fibrinogen

von Willebrand factor

collagen

ADP

Question 9

What kinds of granules do platelets contain?

Answer 9

alpha granules (contain coagulation and growth factors)

dense granules (contain ADP, Ca++ and serotonin)

Question 10

How do you interpret the platelet concentration when the platelets are clumped on the blood smear?