Question

In extrinsic clotting pathway, active factor VI activates factors
(A) X and XI
(B) IX and X
(C) IX and XI
(D) XI and XII.

Answer 1

Hint: The natural action pathway may be a cascade of events that prevents the process of homeostasis. The tangled pathway permits for fast healing and bar of spontaneous haemorrhage. Two paths, intrinsic and extrinsic, originate on an individual basis however converge at a particular purpose, resulting in protein activation. The aim is to ultimately stabilize the thrombocyte plug with a protein mesh.

Complete answer:
The mechanism through which the process of coagulation allows for haemostasis is a series of long step processes that is done through a series of clotting factors. The intrinsic pathway is made up of factors I, II, IX, X, XI, and XII.
The name is given as fibrinogen, prothrombin, Christmas factor, Stuart-Power factor, plasma thromboplastin, and Hageman factor respectively to each of them.
 The extrinsic pathway is made up of factors I, II, VII, and X. Factor VII is called a stable factor. The common pathway consists of factors I, II, V, VIII, X.
Extrinsic Pathway:
The extrinsic pathway is the shorter duration pathway of secondary haemostasis that is a method of constant body temperature.
Once the damage is done to the vessel the endothelial cells release tissue factor which is required to activate factor VII to factor VIIa. Factor VIIa goes and activates factor X into factor \[\mathop X\nolimits_a \]. At this most important point where both extrinsic and intrinsic pathways become one.
 The extrinsic pathway is clinically measured as the prothrombin time (PT).
Some organs are involved in this coagulation mechanism. One such mechanism is that of liver. The liver is responsible for the intrinsic and extrinsic factors and proteins also.
If some damage occurs to the liver the coagulation factor stops working and leads to haemorrhage.

So, our required option is B that is IX and X.

Note:
To prevent and stop over-coagulation, which can cause a huge thrombosis, there are certain processes to keep the coagulation cascade in check. As thrombin acts as an anticoagulant, it also acts as a negative feedback by activating plasminogen to plasmin and stimulating the production of antithrombin (AT). Plasmin acts directly on the fibrin mesh and breaks it down.