In the context of homeostatic control, blood clotting is an example of which type of feedback mechanism?

• A. Negative feedback, because the response reduces the initial stimulus by reversing the change
• B. Negative feedback, because it maintains variables like blood glucose near a set point
• C. Positive feedback, because activated platelets and clotting factors amplify the clotting response until the break in the vessel is sealed
• D. Neither, because it is controlled only by the nervous system and not by feedback mechanisms

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the concept of feedback mechanisms in homeostasis. Negative feedback works to reverse a change and maintain stability, while positive feedback amplifies a response until a specific outcome is achieved.
2. Step 2: Identify the role of blood clotting in the body. Blood clotting is a process that stops bleeding by forming a clot at the site of a vessel injury.
3. Step 3: Analyze how the clotting process works. When a blood vessel is damaged, platelets become activated and release chemicals that attract more platelets and clotting factors, amplifying the response.
4. Step 4: Recognize that this amplification continues until the break in the vessel is sealed, which is characteristic of a positive feedback mechanism rather than negative feedback.
5. Step 5: Conclude that blood clotting is an example of positive feedback because the response enhances the initial stimulus (vessel injury) until the problem is resolved.