Tutorial Notes

Question 1

what is the extrinsic pathway for secondary haemostasis

Answer 1

Tissue factor and Factor VII; released from the damaged tissue.

Initiate secondary haemostasis

Question 2

what is the intrinsic pathway for secondary haemostasis

Answer 2

Amplification side; Factor VIII and IX.

Also Factor XI and XII [not quite as critical as 8 and 9 for amplification part]

Question 3

what is the common final pathway

Answer 3

activate 5 and 10. Which then activate Prothrombin [factor II] to make it become Thrombin.

Thrombin then cleaves fibrinogen [factor I] to become fibrin.

Thrombin also activates 8 and 9 = giving you more 5 and 10 then more thrombin i.e. is needed for proper amplification

Question 4

what are sources of vitamin K

Answer 4

bacteria in the gut, diet leafy green veg

Question 5

why do you get low platelets in liver disease

Answer 5

due to associated with hypersplenism

Question 6

how could you distinguish between liver disease and DIC

Answer 6

D-Dimer:
- in liver disease would be normal

• in DIC would be very high

Question 7

why are oral contraceptive pills a risk factor for thrombosis

Answer 7

promote production of precursor factors in the clotting cascade predisposing to thrombus formation

plus high oestrogen levels mimic pregnancy [which is a risk factor for venous thrombosis]

Question 8

smoking is a risk factor for venous thrombosis - true or false

Answer 8

false

risk factor for ARTERIAL thrombosis

Question 9

when can warfarin not be given

Answer 9

when patient is pregnant

- is teratogenic

Question 10

what does menorrhagia and easy bruising suggest

Answer 10

problem with primary haemostasis

Question 11

why are babies given an injection of vitamin K at birth

Answer 11

do not have bacteria in the gut yet that could help them get vitamin K