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.
A negative negative feedback mechanismMechanism to lower raised levels of something, and to raise reduced levels of something. 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
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.