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Why do we need to maintain a constant internal environment?Negative feedback systems - Higher

Organisms can only function if their internal conditions are kept within a specific range. This is called homeostasis. The endocrine system secretes hormones for homeostasis to occur.

Part of Combined ScienceThe human body - Staying alive

Negative feedback systems - Higher

A negative is an important type of control that is found in homeostasis. It responds when conditions change from the ideal or set point and returns conditions to this set point. There is a continuous cycle of events in negative feedback.

General stages in negative feedback

In general this works in the following way:

  • if the level of something rises, control systems reduce it again
  • if the level of something falls, control systems raise it again
Conditions in the body change from set point, the change is detected and corrective mechanisms are activated. Conditions then return to set point and corrective mechanisms are switched off.
Figure caption,
Negative feedback flowchart

Negative feedback - example

Body temperature is controlled by the hypothalamus in the brain. If the hypothalamus detects that the body is too hot, the response is that the body begins to sweat to try and reduce the temperature back to the correct level. Once the body temperature is back to the correct level, sweating will stop. In the opposite way, if the hypothalamus detects that the body is too cold then the response is that the body begins to shiver to try and raise the temperature back to the correct level. Once the body temperature is back to the correct level the shivering will stop.