Question

Primary hemostasis involves:

A. Platelets, vessel wall, von Willebrand factor (vWF)

B. Factor XI, factor VIII, factor IX

C. Thrombin, fibrinogen, factor XIII

D. Plasminogen activator, plasmin

Answer 1

Primary homeostasis is a major step of blood coagulation; it is an essential feature of the body's mechanism to prevent excessive loss of blood. At any site of injury, there is a need for blood coagulation and this process helps in stopping the blood flow by the formation of a mesh-like structure called blood clot formed of fibrin. Before the thick strong fibrin clot is formed, a simple clot it formed of platelets, this process includes primary homeostasis. This is carried out by the formation of the platelet plug at the site of vascular injury. This is formed to rapidly stop the blood flow.

Answer A. Platelets, vessel wall, von Willebrand factor(vWF)

Platelets are a type of blood cells, that actively participates in the blood clot process.

Vessel wall is composed of the lining of endothelial cells. Any injury to the vessel wall will begin the formation of a platelet plug. The endothelial ling of the area of damage is removed, at this site platelets begin to attach to the collagen layer. These platelets become activated and are able to stick to the vessel wall as well as each other through morphological changes.

von Willebrand factor(vWF), are specialized proteins secreted by endothelial cells which bind to the damaged vascular lining to expose underlying collagen where platelets bind to form platelet plug. When platelets bind to the vWF they become activated and undergo morphological changes like increased surface area and they stick to the vessel wall and each other.

Following this a cascade of blood clot process begins for formation of fibrin clot.