Chapter 1: Overview of the Endocrine System

4.2. Positive feedback

• Positive feedback loops are characterized by the release of additional hormone in response to an original hormone release.
• Thus, positive feedback enhances change.
• Example: Oxytocin during childbirth → uterine contractions → more oxytocin → stronger contractions.
• The initial release of oxytocin begins to signal the uterine muscles to contract, which pushes the fetus toward the cervix, causing it to stretch. This, in turn, signals the pituitary gland to release more oxytocin, causing labor contractions to intensify. The release of oxytocin decreases after the birth of the child.