Figure 1.

The thrombotic and thrombolytic cascades and primordial immune response. The thrombotic pathways (intrinsic and extrinsic) and the thrombolytic (fibrinolysis) pathway involve a complex cascade of protease activation. Solid arrows indicate the conversion to an active protease, while dotted line arrows indicate the activity of the activating upstream protease. A variety of inhibitors are shown, with serpin inhibitors denoted by a serpin protein structural image. Examples of early primordial immune response origins are noted in context of the pathways. MYA, million years ago.