Which example best illustrates positive feedback in a physiological process?

Which example best illustrates positive feedback in a physiological process?

• A. Oxytocin-induced labor contractions
• B. Regulation of body temperature by sweating
• C. Insulin regulation of blood sugar
• D. Blood pressure stabilization by autonomic mechanisms

Answer: (A)

This illustrates a positive feedback loop, where an initial stimulus triggers a response that amplifies the same stimulus until a final event occurs. In labor, cervical stretching stimulates the release of oxytocin, which increases uterine contractions. Those stronger contractions cause more cervical stretching, prompting even more oxytocin release and stronger contractions, continuing until birth ends the cycle. This amplification is the hallmark of positive feedback. The other processes are different kinds of regulation. Sweating in response to heat is negative feedback: the body acts to reverse the deviation and restore normal temperature. Insulin release to lower blood glucose is also negative feedback, restoring normal glucose levels. Blood pressure stabilization via autonomic mechanisms is another negative feedback scenario, counteracting deviations to maintain a stable pressure. Positive feedback is less about maintaining balance and more about pushing a process to a defined endpoint, as in childbirth.

This illustrates a positive feedback loop, where an initial stimulus triggers a response that amplifies the same stimulus until a final event occurs. In labor, cervical stretching stimulates the release of oxytocin, which increases uterine contractions. Those stronger contractions cause more cervical stretching, prompting even more oxytocin release and stronger contractions, continuing until birth ends the cycle. This amplification is the hallmark of positive feedback.

The other processes are different kinds of regulation. Sweating in response to heat is negative feedback: the body acts to reverse the deviation and restore normal temperature. Insulin release to lower blood glucose is also negative feedback, restoring normal glucose levels. Blood pressure stabilization via autonomic mechanisms is another negative feedback scenario, counteracting deviations to maintain a stable pressure. Positive feedback is less about maintaining balance and more about pushing a process to a defined endpoint, as in childbirth.