Question

An important response mechanism in our bodies is blood clotting. The response loop is initiated when injured tissue releases signal chemicals that activate platelets in the blood. An activated platelet releases chemicals to activate more platelets, causing a rapid cycle and the formation of a blood clot.
a)Is blood clotting an example of a positive or negative feedback mechanism? Explain your answer based on the description of the mechanism.

b)Blood clotting must happen quickly in order to be useful to the body. Explain how this type of feedback mechanism is useful for accelerating the clotting process.

c)Imagine that a toxin in the bloodstream denatures the molecules that signal for platelets. Predict how this would affect this feedback mechanism and the person’s body as a result.

Answer 1

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 .