pleasei need help with a homeostasis mechanism [

Question

When a vessel is damaged, chemicals are released from the vessel walls that attract platelets to the site of the damage. As they accumulate, more chemicals that attract more platelets to the area until the bleeding stops. This represents ________ feedback, with the platelets acting as the 

Answer 1

Generally in homeostasis there are either positive or negative feedback loops. In this case, it is the beginning of the repair cycle so a positive feedback loop escalates the process of repair. The damaged vessel leaks chemotactic factors that attract platelets and cells. This is all part of the prostaglandin and inflammation system. The platelets will accumulate and stick together to block the hole in the vessel wall. Eventually they will form a clot.

 

Do you see why this is positive? A few chemicals attract more chemicals and cells, which is why you see swelling at the site of an injury that the body is repairing. Once the bleeding has stopped, the positive feedback loop stops as well.

 

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