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histology of Adrenal glands

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Mohamed Abdullah

Factor XII, also known as Hageman factor, is a plasma protein and zymogen that plays a role in coagulation. It is encoded by the F12 gene and has a structure consisting of two fibronectin-type domains, two epidermal growth factor-like domains, a kringle domain, and a proline-rich region. Factor XII functions to initiate the intrinsic pathway of coagulation by being activated via contact with polyanions like polyphosphates secreted by activated platelets, linking primary hemostasis involving platelet plug formation to secondary hemostasis involving fibrin meshwork formation.

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HAGEMAN FACTOR (COAGULATION FACTOR XII) PREPER BY : BAKIR AL_BAGHDADY
Coagulation factor XII, also known as Hageman factor, is a plasma protein. It is the zymogen form of factor XIIa, an enzyme (EC3.4.21.38) of the serine protease (or serine endopeptidase) class. In humans, factor XII is encoded by by the F12 gene.[5]
STRUCTURE Human Factor XII is 596 amino acids long and consists of two domains, Its heavy chain contains two fibronectin-type domains (type I and II), two epidermal growth factor-like domains, a kringle domain, and a proline- rich region
FUNCTION factor XII is activated by contact to polyanions. Activated platelets secrete inorganic polymers, polyphosphates. Contact to polyphosphates activates factor XII and initiates fibrin formation by the intrinsic pathway of coagulation with critical importance for thrombus formation.
Targeting polyphosphates with phosphatases interfered with procoagulant activity of activated platelets and blocked platelet-induced thrombosis in mice. Addition of polyphosphates restored defective plasma clotting of HermanskyPudlak syndromepatients, indicating that the inorganic polymer is the endogenous factor XII activator in vivo. Platelet polyphosphate-driven factor XII activation provides the link from primary hemostasis (formation of a platelet plug) to secondary hemostasis (fibrin meshwork formation).[9]
histology of Adrenal glands

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histology of Adrenal glands

  • 1. HAGEMAN FACTOR (COAGULATION FACTOR XII) PREPER BY : BAKIR AL_BAGHDADY
  • 2. Coagulation factor XII, also known as Hageman factor, is a plasma protein. It is the zymogen form of factor XIIa, an enzyme (EC3.4.21.38) of the serine protease (or serine endopeptidase) class. In humans, factor XII is encoded by by the F12 gene.[5]
  • 3. STRUCTURE Human Factor XII is 596 amino acids long and consists of two domains, Its heavy chain contains two fibronectin-type domains (type I and II), two epidermal growth factor-like domains, a kringle domain, and a proline- rich region
  • 4. FUNCTION factor XII is activated by contact to polyanions. Activated platelets secrete inorganic polymers, polyphosphates. Contact to polyphosphates activates factor XII and initiates fibrin formation by the intrinsic pathway of coagulation with critical importance for thrombus formation.
  • 5. Targeting polyphosphates with phosphatases interfered with procoagulant activity of activated platelets and blocked platelet-induced thrombosis in mice. Addition of polyphosphates restored defective plasma clotting of HermanskyPudlak syndromepatients, indicating that the inorganic polymer is the endogenous factor XII activator in vivo. Platelet polyphosphate-driven factor XII activation provides the link from primary hemostasis (formation of a platelet plug) to secondary hemostasis (fibrin meshwork formation).[9]