Balance is dynamic
Homeostasis does not mean that a body condition stays at one exact number. It means the body continually adjusts so important conditions remain within a useful range.
A feedback pathway includes a sensor that detects change, a control center that interprets it, and an effector—such as a muscle, gland, or organ—that carries out a response.
Negative feedback pushes back
Negative feedback reduces the original change. If a condition moves too far in one direction, the response pushes it back toward its usual range.
Body-temperature regulation is a familiar example: responses that release heat oppose a rise in temperature, while responses that conserve or generate heat oppose a drop.
Remember these ideas
Key ideas
- Homeostasis maintains conditions within ranges, not at perfectly fixed values.
- A sensor detects change, a control center interprets it, and an effector responds.
- Negative feedback opposes the direction of the original change.
- This lesson explains a concept and is not personal medical guidance.
Make the reasoning visible
Worked example · rising body temperature
- 1
Body temperature rises above its usual range, creating the original change.
- 2
Temperature sensors detect the rise and send information to a control center in the brain.
- 3
The control center activates responses such as sweating and widening blood vessels near the skin, which help release heat.
- 4
Those responses oppose the rise in temperature, so this is a negative-feedback loop.
Try the next step
Trace the direction of a response
Body temperature drops below its usual range and shivering begins. Is this negative feedback, and what evidence supports your answer?
Why does “negative” describe direction rather than whether the response is good or bad?