Summary:
- Most hormones are regulated by feedback mechanisms.
- A feedback mechanism is a loop in which a product feeds back to control its own production.
- Negative feedback keeps the concentration of a hormone within a narrow range.
- This type of feedback brings things back to normal whenever they start to become too extreme.Positive feedback is much less common because it causes conditions to become increasingly extreme.
- The thyroid gland is a good example of this type of regulation.
- It is controlled by the negative feedback loop shown in Figure below.