Final answer:
The intrinsic coagulation cascade involves clotting factors XII, XI, IX, and VIII, which sequentially activate each other, ultimately leading to the activation of factor X and progression to the common pathway. Platelets and endothelial cells contribute to these reactions, and vitamin K is essential for synthesizing many of the clotting factors.
Step-by-step explanation:
The intrinsic coagulation cascade is a complex series of events involving several clotting factors that are present within the bloodstream. These factors are responsible for forming a blood clot when there is damage to tissues or contact with foreign materials. The cascade is initiated by factor XII (Hageman factor), which then activates factor XI. Following this, factor IX is activated, and with the help of factor VIII, an enzyme complex is formed that finally activates factor X (Stuart-Prower factor), leading to the common coagulation pathway.
The ordering and activation of these factors within the intrinsic pathway occur rapidly, often in a matter of minutes. Platelets also play a crucial role in this process, releasing chemicals that accelerate the activation reactions. It is essential to note that the liver, with the aid of vitamin K, produces many of these clotting factors, and calcium (factor IV), is also necessary for this process.
The clotting factors are numbered I through XIII in the order of their discovery, and they all function together to maintain hemostasis—the stopping of bleeding. Some of the factors require vitamin K for their synthesis, which can be consumed in the diet or synthesized by gut bacteria. The intrinsic pathway events lead to the activation of factor X, the start of the common pathway, and ultimately result in the formation of a stable blood clot.