1 / 9

Platelets

Platelets. Size: 1 – 4 Micro meter in diameter Normal Count: 1, 50000 – 300,000 / cu mm or micro liter Live span: 10 days Megakaryocyte 35-160 micron. Platelet membranes contain receptors for Collagen ADP Vessel wall Von Willebrand factor Fibrinogen Glycoprotein.

matthew-mendoza
Download Presentation

Platelets

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Platelets Size: 1 – 4 Micro meter in diameter Normal Count: 1, 50000 – 300,000 / cu mm or micro liter Live span: 10 days Megakaryocyte 35-160 micron

  2. Platelet membranes contain receptors for • Collagen • ADP • Vessel wall Von Willebrand factor • Fibrinogen • Glycoprotein

  3. Platelets cytoplasm contain • Actin • Myosin • Thrombosthenin • Glycogen • Lysosomes • Fibrin stabilizing factor • Granules • Dense granules Contains non protein substances e.g. Serotonin, ADP, Ca and other nucleotides. II. Alpha granules: Secrete proteins e.g. Clotting factors, platelet derived growth factor (PDGF), Von Willebrand factor.

  4. Regulation of Platelet Production • Thrombopoietin • Erythropoietin • Menstrual cycle • Adrenaline • Injury • Hypoxia • Smoking • Vitamin deficiency

  5. Hemostasis Arrest of bleeding/ prevention of blood loss Involves three steps A. Vascular spasm • Inherent vascular response • Sympathetically induced vasoconstriction • Vasoconstrictor substance e.g Thromboxane A2. B. Formation of platelet plug • Platelet adhesion • Platelet activation • Platelet aggregation. C. Clot formation • Intrinsic system • Extrinsic system • Growth of fibrous tissue in clot

  6. Platelet Plug

  7. Functions of Platelet Plug • Seals the break in the vessel • Strengthens loose plug –actin and myosin • Reinforce initial vascular spasm—serotonin, epinephrine, thromboxane A2 • Enhances blood coagulation

  8. Thrombocytopenia Decreased Number of platelets in the blood Causes. • Idiopathic • Secondary • Pancytopenia • Increased destruction of platelets • Hypersplenism • Leukemia

  9. Thrombocytosis Increase no of platelets in the blood Causes. • After acute haemorrhage • Splenectomy • Polycythemia vera

More Related