Haem haemostasis

Question 1

what are the steps of Haemostasis?

Answer 1

Vascular spasms
platelet plug formation
coagulation
clot retraction and repair
fibrinolysis

Question 2

What is vascular spasms

Answer 2

1).Contraction of the blood vessels
Endothelium secrete endothelin to activate PiP2
Pip2 activates smooth muscle contraction

2). Myogenic- direct injury causes smooth muscle contraction

3). Nociceptor activation- inflammatory chemicals eg histamines initiate pain reflex which causes vasoconstriction.

Question 3

platelet formation

Answer 3

damage blood vessels means decreased anticoagulant factors
VWF enables adhesion and aggregation
Adhesion: VWF enter endo cells and bind to GP1b (of platelets)
Activation- platelets are activated by changing shape
Aggretation-platelets bind to other platelets
platelets bind to one another by GPIIb/IIIa
Fibrinogen bind platelets together

Question 4

what are the three storage granules of platelets

Answer 4

Alpha granules-contains proteins
VWF
PDGF-long term healing
PF4, Factor V

Dense granules contains non-proteins
ADP
TXA2

Lysosomes

Question 5

What is responsible for platelet activation?

Answer 5

1).ADP: bind to PiP2
TXA2 bind to TP

Question 6

what are the steps of coagulation?

Question 7

non-proteins responsible for smooth wall contraction

Answer 7

TXA2 and Seratonin