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Most endocrine tissues use a negative feedback mechanism for homeostasis. Which of the following involves a positive feedback mechanism? Group of answer choices cortisol insulin oxytocin thyroid

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Answer:

The correct answer is: Oxytocin.

Explanation:

Feedback mechanisms are key elements in the regulation of hormone release and, in the human body, most endocrine systems work by making use of negative feedback, which means that the response generated by the release of the peripheral hormone (for example, insulin), will lead to an inhibition of the stimulus that made the release of said hormone possible - this is very important to control homeostasis.

Positive feedback, on the other hand, is the opposite. This type of feedback mechanism, which is not as common as negative feedback, happens when the peripheral hormone is released and this stimulates the tissue that released the hormone that stimulated the release of the peripheral hormone - this is done so the hormone effect is amplified more and more.

To better illustrate these mechanisms, here are some examples of each:

  • Insulin. After having a meal, the blood sugar levels rise, which triggers the release of insulin, a hormone that decreases blood sugar levels (glycemia). When this decrease in glycemia is produced, the release of insulin is stopped. This is negative feedback. Cortisol and thyroid hormones are also examples of negative feedback.
  • Oxytocin. This hormone is released from the posterior pituitary gland during labor to produce the contractions of the uterus, which will push the baby through the birth canal. The presence of oxytocin will lead to the release of more oxytocin, so the muscle contractions can increase. This is an example of positive feedback.