Topic/Source: The Blood Clotting Cascade. Vessel injury triggers two pathways. Extrinsic Pathway (FAST): Tissue Factor activates Factor VII. Intrinsic Pathway (SLOW): Exposed collagen activates Factor XII. Both merge at Factor X. Factor X converts Prothrombin into Thrombin. Thrombin converts Fibrinogen into Fibrin. Fibrin mesh traps RBCs to form a clot. Style: Serious Subject. Design: Clean white background, dark navy text, teal accents. Minimalist medical aesthetic. No stock photos of random people.