Blood coagulation, also known as hemostasis, is a complex process that stops bleeding and maintains the integrity of the vascular system. It consists of several phases, among which primary and secondary hemostasis, anticoagulation and fibrinolysis. 

Primary Hemostasis:

1. Vasoconstriction: Upon injury to the blood vessels, the contract as consequence of the smooth muscles of the vessel wall, which constricts blood flow and diminishes blood loss. 

2. Formation of a primary hemostatic plug: Upon injury to a blood vessel, blood platelets will adhere to the protein von Willebrand factor that has recognized subendothelial collagen fibers. After adhesion of the blood platelets, they become activated that allows them to bind to other platelets forming the primary hemostatic plug.  

Secondary Hemostasis: 

1. Activation of the coagulation cascade: Upon injury to the vessel, the initiator of coagulation, tissue factor, becomes exposed to the flowing blood. This allows a cascade of enzymatic reactions to occur involving several coagulation factors that result in the formation of insoluble fibrin. 

 2. Formation of a clot: Fibrin fibers will be formed strengthening the primary hemostatic plug that povides a strong barrier preventing blood loss and allows repair of the injured vessel. 

Anticoagulation and Fibrinolysis: 

 1. Natural antiocoagulants: The body produces natural anticoagulants such as antithrombin, protein C and protein C, that inhibit coagulation and prevenet unwanted clot formation. 

 2. Fibrinolysis: This is the process that breaks down, dissolves, blood clots. Plasminogen, an inactive precursor, becomes activated to plasmin by several activators, such as tissue-type plasminogen activator and urokinase. Plasmin breaks down fibrin in soluble fragments, also known as D-dimers, which allows restoration of blood flow.  

In summary, blood coagulation is a well-regulated process that is crucial in the prevention of bleeding en maintenance of vascular integrity. It consists of several phases that are intimately connected to maintain the balance between clot formation and clot dissolution. Extensive knowledge of these processes is essential to understand the pathophysiology of blood coagulation disorders and the development of effective treatments.