Answer:
A blood vessel is severed.
Blood and blood components leak out the breaks.
Chemicals are released from the injury site and from underlying callogen.
The smooth muscle in the vessel wall contracts near the injury point, reducing blood loss.
Fibrinogen is converted to fibrin.
The platelets become activated making them spiked and sticky.
Fibrin forms a mesh that traps more platelets and erythrocytes, producing a clot.
Explanation:
Hemostasis is the process by which the body prevents and stop blood loss through bleeding.
Hemostasis occurs in three steps:
1. Vasoconstriction: Once a blood vessel is severed or cut, the smooth muscles of the blood vessels start to constrict or get narrower around the severed vessel in order to reduce blood flow through it. This vasoconstriction occurs in response to chemicals released from the cut vessel and the underlying collagen.
2. Platelet-plug formation: the platelets become activated by a glycoprotein called Von Willebrand factor (vWF), which is found in plasma and begin to clump together sticking together. This is known as primary hemostasis.
3. Clot formation: in response to platelet-plug formation, several clotting factors are activated which eventually convert fibrinogen to fibrin. Fibrin is mesh-like and holds the platelets as well as red and white blood cells in place, thereby forming blood-clots over the wound.
