Hemostasis

Hematology

1. LET YOUR LIGHT SHINE DEP NO:- 17-PML-014 VAMSI KUMAR HAEMATOLOGY

2. HEMOSTASIS heamostasis HAEMOSTASIS vamsi kumar

3. DEFINITION From the Greek meaning THE STOPPAGE OF BLOOD FLOW * The term haemostasis means prrevention of blood loss. *Haemostasis is the arrest of bloood flow and control of haemorrage from an injurred blood vessels OR *It is a process by which bleeding at any site is arrested by formation of haemostatic plug. OR *Maintenance of normal blood flow within the circulatory system.

4. Overview of Hemostasis There are TWO main components of hemostasis.... 1. PRIMARY heamostasis refers to PLATLET ADHESSION PLATLET AGGREGATION PPLATLET PLUG FORMATION 2. SECONDRY heamostasis refers to the deposition of insoluble fiibrin ,which is generated by the proteolytic coagulation cascade reactions.

5. Some Important TERMS to know... HEAMOSTASIS :-normal response to stop blood using pllatlets and let tghe coagulation cascade. THROMBOSIS :-Pathologic formation of clots..(deep vein thrombosis) HEMORRHAGE :-Bleeding. COAGULOPATHY :-A defect in Coagulation,pathologic Bleeding..(e.g. Hemophilia) PRIMARY HEMOSTASIS :- A formation of platlet plug through the platlets Gp1b-V-IX receptor(connects with t subendothelial Von Wiillibrand Factor) and GpVI receptor (connects with the subendothelial COLLAGEN)

6. CONTINUE... SECONDRY HEMOSTASIS :-Progression of the coagulation cascade resulting in the formation of an insoluble fibren mesh to strenghten the platlet plug...

7. STEPS IN PRIMARY HEAMOSTASIS Definition: Primary hemostasis is defined as the formation of the primary platelet plug . 1.Local vasoconstriction 2.Platelet adhesion: Platelets adhere to the exposed subendothelial matrix (directly or indirectly via vWf). 3.Platelet activation: Once platelets adhere, they then become activated and recruit (and activate) additional platelets to the injured site. Also, thrombin generated by the coagulation cascade is an extremely powerful platelet activator. 4.Platelet plug formation: Fibrinogen forms bridges between activated platelets to form the platelet plug

8. II.STEPS IN SECONDRY HEMOSTASIS Definition : Secondary hemostasis is defined as the formation of insoluble, cross-linked fibrin by activated coagulation factors, specifically thrombin. Fibrin stabilizes the primary platelet plug, particularly in larger blood vessels where the platelet plug is insufficient alone to stop hemorrhage.

9. SECODRY HEMOSTASIS.... The goal of secondary hemostasis is to stabilize the platelet aggregate by weaving a meshwork of fibrin to cement the thrombus. In vitro, the classic coagulation cascade maintains this role. The intrinsic pathway (Factors VIII, IX, XI, XII) and the extrinsic pathway (Factor VII and Tissue Factor) join to activate Factor X and the common pathway. The end result is the formation of thrombin, which cleaves fibrinogen to fibrin and thus the clot can be stabilized.

10. CLOTTING FACTORS The clotting factors are the group of chemicals that are constant circulation in the blood or present in tissues of the blood vessels. These compounds are responsible for the formation of a blood clot. Clotting factors are usually inactive but once there is tissue injury to the wall of the blood vessel, the first factor is activated. This has a cyclical effect with each factor activating the next. The ultimate aim is for these clotting factors to eventually convert the necessary components that will form a blood clot.

11. PATHWAYS IN COAGULAION MECHANISM 1. INTRINSIC PATHWAY 2.EXTRINCIC PATHWAY 3.COMMON PATHWAY

12. 1.INTRINSIC PATHWAY

13. COMMON PATHWAY

14. SCREENING AND DIAGNOSING BLEEDING DISORDERS