Brainlag PlusHigher: how the pituitary and thyroid hold thyroxine steady by negative feedback, reading TSH and thyroxine test results, and why adrenaline is a different kind of response.
What negative feedback means
Many levels in the body are held close to a set value: blood glucose, body temperature, water, and the hormone thyroxine.
In each case the body uses negative feedback: a change away from normal is detected, and the response pushes the level back the other way.
- A level changes (it rises or falls)
- The change is detected
- A response reverses the change
- The level returns to normal, and the response stops
Negative feedback always works against the change. If a response made the change bigger, it would not be negative feedback.
The rest of this lesson and its 12 practice questions are in Plus.
Screen 1 of 5, free to read.
- 12 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards