Question

Following are the examples of negative feedback system except:

• A. Body temperature regulation
• B. Blood glucose maintenance
• C. Blood clotting
• D. Blood pressure maintenance

Hint:

Negative feedback maintains homeostasis by reversing changes, whereas positive feedback amplifies a process until its goal is achieved, such as in blood clotting.

Answer 1

The Correct Option is C

Step 1: Understanding negative feedback systems. A negative feedback system works to maintain homeostasis by counteracting changes in physiological parameters. 
For instance: 
- Body temperature regulation: Uses mechanisms like sweating and shivering to restore temperature balance.
- Blood glucose maintenance: Involves insulin and glucagon to regulate blood sugar levels. 
- Blood pressure maintenance: Adjusts heart rate and vessel dilation to stabilize blood pressure. 

Step 2: Positive feedback in blood clotting. Blood clotting is an example of a positive feedback system. Once a clot begins to form, it releases signals that amplify clotting activity until the process is complete, which is opposite to negative feedback mechanisms. 

Step 3: Why other options are correct examples of negative feedback. - Body temperature, blood glucose, and blood pressure regulation are all examples of negative feedback systems, where deviations are corrected to maintain balance.

Answer 2

The question asks which of the four listed body processes is NOT an example of negative feedback. Let's check how each one actually behaves once it starts.

1. Body temperature regulation: When body temperature rises above the set point, the body sweats to cool down; when it drops, the body shivers to generate heat. Both responses push the temperature back toward normal, which is the defining pattern of negative feedback.
2. Blood glucose maintenance: When blood sugar rises, insulin is released to bring it down; when it falls, glucagon is released to bring it back up. Each hormone counteracts the deviation, again fitting the negative feedback pattern.
3. Blood clotting: Once a blood vessel is injured and clotting begins, activated clotting factors trigger the activation of even more clotting factors in a cascade, amplifying the response rather than damping it down. This self-reinforcing pattern, where the output strengthens the very process that produced it, is a positive feedback loop, not negative feedback.
4. Blood pressure maintenance: When blood pressure rises, baroreceptors trigger a drop in heart rate and vessel dilation to bring it back down; when pressure falls, the opposite adjustments occur. This correction toward a set point is again negative feedback.

Three of the four processes correct a deviation back toward a stable set point, which is what negative feedback means, while clotting instead escalates once triggered until the clot is complete, marking it as the exception.

So the correct answer is Blood clotting.