1) A blood clotting or coagulation is an example of positive feedback mechanism. It is a mechanism where the output enhances the original stimulus: platelets release chemicals that attract more platelets.
2) This mechanism starts when the wall of the
vessel releases chemicals that initiate the formation of a blood clot (platelet congregation). As more platelets gather, more chemicals are released and the process gets faster and faster until the clot is formed.
3) The positive feedback mechanism might be broken and consequently, the blood can’t clot properly. Bleeding disorder can occur because of the excessive or prolonged bleeding .