Lecture 3 coagulation

Question 1

What organ makes clotting factors?

Answer 1

The liver

Question 2

Is coagulation part of primary or secondary hemostasis?

Answer 2

Secondary, the primary hemostasis only consists of the the platelet plug that is formed.

Question 3

What pathways make out the coagulation pathway?

Answer 3

Extrinsic and intrinsic pathway

Question 4

Describe the extrinsic pathway

Answer 4

Following platelet plug formation, tissue injury causes expression of **tissue factor (TF) **and together with Factor VIIa, it will activate many molecules of Factor X to become Factor Xa.

–> The extrinsic pathway is Initiated by the exposure of blood to a negatively charged surface, which activates Factor XII. This activates Factor **XI, IX **and VIII in the intrinsic pathway.

Question 5

How does the intrinsic pathway continue after its activated by the extrinsic pathway?

Answer 5

Factor VIIIa will activate Factor X. So the intrinsic and extrinsic pathway will both activate Factor X.
- Factor Xa and Factor Va are the beginning of the common pathway.

Question 6

Describe the common pathway

Answer 6

Factor Xa and Factor Va as cofactor, activate prothrombin (Factor II) to become thrombin (Factor IIa). Thrombin will convert fibrinogen into fibrin (Factor Ia).

–> Local generation of fibrin will turn into meshes and reinforces the platelet plug formation, which is formed from the primary hemostasis. The bleeding has now successfully stopped.

Question 7

Name a negatively charged surface outside the body

Answer 7

A blood tube

Question 8

Name a negatively charged surface inside the body

Answer 8

extracellular phospholypate, DNA and RNA. This leads to blood clotting/inflammation.

Question 9

So what cofactors does the extrinsic pathway have?

Answer 9

Tissue factor (TF), Factor VIIa, factor X and factor XII.