All of the following are true about blood coagulation, EXCEPT:
Contact with negatively charged surfaces activates the Intrinsic pathway of coagulation and not the Extrinsic pathway. Intrinsic pathway is also referred to as 'contact pathway' and factor XII is also known as contact factor for its role in the initiation of coagulation on contact with negatively charged surfaces. Extrinsic pathway is activated by tissue factor a cellular lipoprotein exposed at sites of tissue injury Ref: Robbins pathologic basis of disease 6th edn/page 977.
Factor X is pa of both intrinsic and extrinsic pathways
Extrinsic pathway is activated by contact with negatively charged surfaces
Intrinsic pathway can be activated in vitro
Calcium is required in several steps of coagulation