blood clotting


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seminar about blood clotting by Hina Yaseen Ranjha from Sargodha Pakistan...further can contact at

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blood clotting

  1. 1. Contents Hemostasis( 1 Vascular Phase( 2 Platelet Phase( 3 Clot formation( 4 Clot retraction( 5 Fibrinolysis( 6
  2. 2. Hemostasis
  3. 3. Hemostasis is process of* forming clots in walls of damaged blood vessels and preventing blood loss, while maintaining blood in a fluid state within vascular system Haima + Stasis Prevent blood loss
  4. 4. Stages of Hemostasis •
  5. 5. I. VASCULAR CONSTRICTION Immediately blood ( 1 • vessel is cut or ruptured. 2( Stimulus of trauma to vessel causes wall of . vessel to contract • This immediately( 3 reduces the flow of blood .from vessel rupture
  6. 6. More a vessel( 4 is traumatized. 5( The greater the degree of spasm. 6( This local vascular spasm can last for many minutes or even hours
  7. 7. Vascular Phase
  8. 8. II. FORMATION OF THE PLATELET PLUG When platelets come in contact with a damaged vascular surface, they immediately change their : characteristics Begin to swell( 1 Assume irregular forms with ( 2 numerous irradiating pseudopods protruding from ;their surfaces
  9. 9. Their contractile proteins ( 3 contract and cause release of granules contain multiple active ; factors They become sticky so that(4 ;they stick to collagen fibers •
  10. 10. III. BLOOD COAGULATION IN THE RUPTURED VESSEL Clot begins to develop in 15 to( 1 • 20 seconds if trauma of vascular wall severe 2(And in 1 to 2 minutes if the trauma minor 3( Activator substances both from traumatized vascular wall and from platelets and blood proteins adhering to traumatized vascular ..wall initiate clotting process
  11. 11. Within 3 to 6( 4 minutes after rupture of a vessel, if vessel opening is not too large, entire opening or broken end of vessel is filled with .clot After 20 minutes to( 5 an hour, clot retracts; .this closes vessel
  12. 12. CLOT CLOT is composed of meshwork of fibrin fibers( 1 • running in all directions and entrapping blood cells, . platelets, and plasma Fibrin fibers also adhere to damaged surfaces of( 2 blood vessels; therefore, the blood clot becomes adherent to any vascular opening and thereby .prevents blood loss •
  13. 13. Coagulation process When tissues( 1 are exposed enzyme thrombin .is released Thrombin( 2 activates clotting factor in platelets causing them to .become sticky
  14. 14. Coagulation Process The platelets begin( 3 to stick together at wound site binding .to exposed fibers Platelets release( 4 several chemicals and change their shape to fit .formation of plug .
  15. 15. Then, a fibrin mesh forms( 5 and insures the clot will . stay Finally, blood clot must( 6 dissolve in order to restore normal blood flow to the vessel
  16. 16. CLOT RETRACTION Platelets are become attached to fibrin, fibers in( 1 such a way that they actually bond different fibers .together Platelets release procoagulant substances, one of (2 which is fibrin-stabilizing factor, which causes more and more cross-linking bonds between adjacent .fibrin fibers Platelets themselves contribute directly to clot( 3 contraction by activating platelet thrombosthenin, actin, and myosin molecules (contractile proteins( and cause strong contraction of the platelet attached .to the fibrin • • •
  17. 17. This helps compress fibrin( 4 • meshwork into a smaller mass. 5( Contraction is activated or accelerated by thrombin as well as by . calcium ions released from platelets As clot retracts,edges of broken( 6 • blood vessel are pulled together, thus contributing to ultimate state of haemostasis
  18. 18. Fibrinolysis Process wherein a fibrin clot, product of coagulation, is broken down. Its main enzyme plasmin cuts fibrin mesh at various places, leading to production of circulating fragments That are cleared by other proteases or by the kidney and liver HEMOSTASIS
  19. 19. FIBROUS ORGANIZATION ((DISSOLUTION OF THE CLOT It can become invaded by fibroblasts, which ( 1 subsequently form connective tissue all through . clot . it can dissolve( 2 The usual course for a clot that forms in a small hole of a vessel wall is invasion by fibroblasts, beginning within a few hours after clot is formed. This continues to complete organization of the clot into .fibrous tissue within about 1 to 2 weeks •
  20. 20. When additional blood coagulates to form a larger clot such as blood that has leaked into tissues, special substances within the clot itself usually become activated And these then function as enzymes to .dissolve the clot
  21. 21. How does the blood clotting process work_ - - Scientific Video and Animation Site.flv
  22. 22. Thank You For Your !Attention