What is a feedback loop and how do negative and positive feedback differ? Provide typical examples.

What is a feedback loop and how do negative and positive feedback differ? Provide typical examples.

• A. A cycle that never reaches a set point; examples include body temperature stability (positive) and blood clotting (negative).
• B. A process that reduces variation.
• C. A negative feedback loop returns a variable to a set point; a positive feedback loop amplifies change.
• D. A positive feedback loop returns a variable to a set point.

Answer: (C)

Feedback loops regulate internal conditions by sensing a signal and adjusting the response. Negative feedback keeps things steady by correcting deviations and returning to a set point, while positive feedback amplifies changes and pushes a system toward a final outcome. In this sense, a negative feedback loop helps restore balance—for example, body temperature: when you get too hot, mechanisms like sweating and vasodilation act to cool you down back toward normal temperature; when you’re cold, shivering and vasoconstriction help raise your temperature back to normal. Glucose regulation works similarly: after a meal glucose rises, and insulin is released to lower it back toward baseline. Positive feedback, on the other hand, drives change rather than restoring it. A classic example is the blood clotting cascade, where activated platelets trigger more platelets to join the clot, amplifying the response until the clot forms. Another well-known example is the chain of uterine contractions during childbirth, where oxytocin increases contractions in a loop until delivery occurs. So the correct description is that a negative feedback loop returns a variable to a set point, while a positive feedback loop amplifies change. The other statements mix up these ideas or oversimplify the concept.

Feedback loops regulate internal conditions by sensing a signal and adjusting the response. Negative feedback keeps things steady by correcting deviations and returning to a set point, while positive feedback amplifies changes and pushes a system toward a final outcome.

In this sense, a negative feedback loop helps restore balance—for example, body temperature: when you get too hot, mechanisms like sweating and vasodilation act to cool you down back toward normal temperature; when you’re cold, shivering and vasoconstriction help raise your temperature back to normal. Glucose regulation works similarly: after a meal glucose rises, and insulin is released to lower it back toward baseline.

Positive feedback, on the other hand, drives change rather than restoring it. A classic example is the blood clotting cascade, where activated platelets trigger more platelets to join the clot, amplifying the response until the clot forms. Another well-known example is the chain of uterine contractions during childbirth, where oxytocin increases contractions in a loop until delivery occurs.

So the correct description is that a negative feedback loop returns a variable to a set point, while a positive feedback loop amplifies change. The other statements mix up these ideas or oversimplify the concept.