Multiple Choice
Which of the following is the best example of negative feedback?
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7. Energy and Metabolism
Negative & Positive Feedback
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Which of the following hormones has effects that involve positive feedback loops?
A
Cortisol
B
Insulin
C
Parathyroid hormone (PTH)
D
Oxytocin
Verified step by step guidance1
Understand the concept of positive feedback loops: Positive feedback loops amplify a response or process, rather than stabilizing it. This is in contrast to negative feedback loops, which work to maintain homeostasis by counteracting changes.
Review the function of oxytocin: Oxytocin is a hormone primarily involved in childbirth and lactation. During childbirth, oxytocin stimulates uterine contractions, and these contractions, in turn, stimulate the release of more oxytocin, creating a positive feedback loop.
Compare oxytocin to the other hormones listed: Cortisol, insulin, and parathyroid hormone (PTH) are regulated by negative feedback mechanisms. For example, cortisol levels are controlled by the hypothalamic-pituitary-adrenal axis to maintain balance, insulin regulates blood glucose levels, and PTH adjusts calcium levels in the blood.
Identify the key characteristic of oxytocin's mechanism: The positive feedback loop of oxytocin is unique because it enhances the process it is involved in (e.g., stronger uterine contractions during labor or milk ejection during breastfeeding).
Conclude that oxytocin is the correct answer because it is the only hormone in the list that operates through positive feedback loops, amplifying its effects during specific physiological processes.
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