Table of Contents
- 1 What are the 3 clotting factors?
- 2 Which clotting factor is part of the extrinsic pathway?
- 3 What are the 4 clotting factors?
- 4 What are the clotting factors and their functions?
- 5 Which coagulation factors are vitamin K dependent?
- 6 What test is used to measure the intrinsic pathway?
- 7 What does intrinsic and extrinsic pathway mean?
What are the 3 clotting factors?
The following are coagulation factors and their common names:
- Factor I – fibrinogen.
- Factor II – prothrombin.
- Factor III – tissue thromboplastin (tissue factor)
- Factor IV – ionized calcium ( Ca++ )
- Factor V – labile factor or proaccelerin.
- Factor VI – unassigned.
- Factor VII – stable factor or proconvertin.
Which clotting factor is part of the extrinsic pathway?
The extrinsic pathway consists of the transmembrane receptor tissue factor (TF) and plasma factor VII/VIIa (FVII/FVIIa), and the intrinsic pathway consists of plasma FXI, FIX, and FVIII. Under physiological conditions, TF is constitutively expressed by adventitial cells surrounding blood vessels and initiates clotting.
What is the first clotting factor that the extrinsic and intrinsic pathways have in common?
Factor XII is considered the coagulation factor first activated in the intrinsic pathway. Upon activation, XIIa acts upon factor XI, and the cascade proceeds through factor IX to also activate factor X to trigger the common pathway.
Which clotting test is used to identify issues in the intrinsic pathway of coagulation?
The activated partial thromboplastin time (aPTT) is used to evaluate the intrinsic and common pathways of coagulation.
What are the 4 clotting factors?
The common pathway includes clotting factors X, V, II, I, and XIII.
What are the clotting factors and their functions?
Coagulation factors
| Number and/or name | Function |
|---|---|
| I (Fibrinogen) | Forms clot (fibrin) |
| II (Prothrombin) | Its active form (IIa) activates I, V, VII, VIII, XI, XIII, protein C, platelets |
| III (Tissue factor, Tissue thromboplastin) | Co-factor of VIIa (formerly known as factor III) |
Why are the clotting factors pathways labeled as intrinsic and extrinsic?
This process occurs via two pathways, which unite downstream to form the common pathway to faciliate haemostasis. These are: The extrinsic pathway: This is triggered by external trauma which causes blood to escape the circulation. The intrinsic pathway: This is triggered by internal damage to the vessel wall.
What triggers intrinsic pathway?
The intrinsic pathway is activated by trauma inside the vascular system, and is activated by platelets, exposed endothelium, chemicals, or collagen. This pathway is slower than the extrinsic pathway, but more important. It involves factors XII, XI, IX, VIII.
Which coagulation factors are vitamin K dependent?
Prothrombin, FVII, FIX, protein C, and protein S are vitamin K-dependent clotting factors or proteins strictly related to blood coagulation.
What test is used to measure the intrinsic pathway?
When the aPTT test is performed in conjunction with prothrombin time (PT) test, which is used to evaluate the extrinsic and common pathways of the coagulation cascade, a further clarification of coagulation defects is possible.
What activates the intrinsic pathway?
The intrinsic pathway is initiated by the activation of factor XII by certain negatively charged surfaces, including glass. High-molecular-weight kininogen and prekallikrein are two proteins that facilitate this activation.
Are they three clotting pathways?
The clotting cascade occurs through two separate pathways that interact, the intrinsic and the extrinsic pathway. The extrinsic pathway is activated by external trauma that causes blood to escape from the vascular system. This pathway is quicker than the intrinsic pathway.
What does intrinsic and extrinsic pathway mean?
Intrinsic and extrinsic pathway are two separate pathways involved in the formation of a blood clot during a damage to a blood vessel. The intrinsic pathway is activated by a trauma inside blood vessels. The extrinsic pathway is activated by a trauma to an external surface of the body.