問一個Blood coagulation 過程中的小疑問

Factor VIII 嚴格一點說不完全是局限於 intrinsic pathway。大部分的 coagulation factors 都不是只在單一的 intrinsic/extrinsic pathway 中活化，它們也是會相互影響到另一個pathway 的.


Although the concept of "intrinsic" and "extrinsic" pathways served for many years as a useful model for coagulation, more recent evidence has shown that the pathways are not, in fact, redundant but are highly interconnected.
For example, the tissue factor/VIIa complex activates not only factor X but also factor IX of the intrinsic pathway.
Furthermore, patients with severe factor VII deficiency may bleed even though the intrinsic pathway is intact.
Likewise, the severe bleeding associated with deficiencies of factors VIII or IX would not be expected if the extrinsic pathway alone were sufficient to achieve normal hemostasis.