Hemostasis

Question 1

What is hemostasis?

Answer 1

It is the process by which blood vessels are repaired after injury.

Question 2

How does hemostasis starts?

Answer 2

Its starts as a vascular contraction as an initial reaction to the injury, then clot formation and finally removal of clot when the repair to injury is done.

Question 3

How many stages does hemostasis occur in?

Answer 3

1. Vascular phase
2. Platelet phase
3. Coagulation phase
4. Fibrinolysis phase

Question 4

What is the first phase and what occurs?

Answer 4

Vascular phase
The injuries to the blood vessels causes it to constrict, slowing the flow of blood.

Question 5

What is the second phase and what occurs?

Answer 5

Platelet phase
It comprises the primary hemostasis.
Injury to the endothelial lining causes platelets to adhere (stick to) to it.
Additional platelets stick to it finally forming a temporary platelets plug in a process called aggregation.

Question 6

What is the third phase and what occurs?

Answer 6

Coagulation phase
Involves interactions of coagulation factors that convert the temporary platelet plug to stable fibrin clot.
Coagulation cascade involves an intrinsic system and extrinsic system.

Question 7

What is the fourth phase and what occurs?

Answer 7

Fibrinolysis phase
This the breakdown and removal of the clot. As the tissue repairs start, plasmin (enzyme) starts breaking down the fibrin in the clot.