Platelets and Hemolysis

What are the three phases of hemostasis and their purpose?

1. Primary hemostasis - initial plug formation

2. Secondary hemostasis - fibrin formation

3. Tertiary hemostasis - Fibrinolysis

What are the functions of platelets?

• Maintain vascular integrity

• Responsible for primary hemostasis

• Provide an environment favorable to secondary hemostasis

• Promote vascular healing

• Role in inflammation

What cell do platelets come from?

Megakaryocyte

What is the typical platelet count?

100,000 to 700,000/ uL

What is a feature of equine platelets?

They stain faintly

VonWillebrand factor

• protein

• present in endothelial cells and megakaryocytes

• Involved in platelet adhesion and aggregation

• Stabilizes FVIII of coagulation

What are the steps in primary hemolysis?

• Activation: release of granule contents

• Shape change

• Adhesion: platelet to sub-endothelium (vessel)

• Aggregation: platelet to platelet

What are some kinds of superficial bleeding?

Ecchymosis and Petechiae

What are some clinical signs of thrombocytopenia/ thrombopathia?

• Superficial bleeding

Spontaneous bleeding occurs when platelet count is —-

< 30,000/ul

How should you always check automated platelet counts?

With a blood smear