Homeostasis Is a technical term for the process of maintain a constant internal environment despite external changes. The internal environment, compromises; blood, tissue fluid, body cell contents and all the metabolic processes taking place. Constant in this instance is not absolute or fixed it is much more flexible and dynamic as it refers to the physical and chemical composition being kept within a limited range or variables for maximum efficiency, well-being of the whole body and indeed the maintenance of life itself. The limited range of variables is said to be closely regulated.
Negative feedback as a form of regulation
Feedback control systems
This occurs when a n important variable sometimes known as a key variable e.g. pH of blood and tissue fluid, deviates from the accepted range from the accepted range or limits which then triggers responses that return the variable to within the ‘normal range’. Deviation produces a negative response to counteract the deviation. An example of a negative feedback system within the body is the liver when blood glucose levels fall, the glycogen from the liver is converted into glucose in order raise the energy levels in cells which is crucial. Vital organs that help to control the homeostatic mechanisms are the brain and nervous system. These vital organs help use to anticipate when key variables might rise and fall beyond the accepted range, for example; if it has been several hours since you have ate a meal and you are starting to feel tired and cold you will try to eat a warm energy giving meal to counteract these feelings. This can be called ‘feed forward’ as you are taking steps to avoid a low energy state before it has even happened.
Negative feedback systems require the following; receptors to detect change, a control centre to receive the information and process the response, and effectors to reverse the change and re-establish the original state.
Most control centres are located in