1. Platelets Matea Mrčelić, 2 nd year University of Zagreb, School of Medicine 2013/2014 Mentor: A. Žmegač Horvat

2. Definition Small colorless anucleate disk-like body of mammalian blood that assists in blood clotting

3. Process of differentiation helped and accelerated by thrombopoietin Each megakaryocyte produces 5,000 – 10,000 platelets Last step of thrombopoiesis - in bone marrow or in circulation Lifespan: 10 days, old platelets destroyed in spleen

4. Function Hemostasis Providing platelet phospholipid Carrying coagulation factors and clot retraction Platelet plug Secretory function Producing inflammatory and growth factors ThromboxaneAnti-heparin

5. Platelet count Included in complete blood count Normal range: 150,000 – 300,000 per microliter Can be combined with platelet function test Useful test for patients receiving anticoagulant therapy

6. Thrombocytopenia Decrease of platelet count - below 50,000 per microliter Symptoms: easy bruising, frequent bleeding from the gums, nose, or GI tract, thrombocytopenic purpura Cause: inherited, medications, chemotherapy, alcoholism Treatment: splenectomy or blood transfusion

7. Easy bruising Thrombocytopenic purpura

8. Thrombocytosis Having more than 450,000 platelets Primary and secondary – difference in causes Symptoms: spontaneous blood clots in the arms and legs, which if untreated can lead to heart attack and stroke Treatment for primary thrombocytosis: plateletpheresis

9. References Guyton and Hall Textbook of Medical Physiology, 11 th Edition http://www.platelet- research.org/1/function_hemo.htm#http://www.platelet- research.org/1/function_hemo.htm# http://www.hopkinsmedicine.org/heart_vascula r_institute/clinical_services/centers_excellence /womens_cardiovascular_health_center/patien t_information/health_topics/platelets.html