Homeostasis is the term used to describe the constant state of the internal environment. The body strives to maintain a level state balance, therefore is constantly adjusting. Homeostasis regulation is controlled through both the nervous and endocrine systems. The homeostasis process runs through a path which involves three elements: the detector, the control centre and the effectors. The receptor picks up internal or external information from the environment, and sends it to the control centre. The control centre assesses the information and decides what action to take, then sends the signals to the effectors to process the decision. without the process of homeostasis the body would not be able to function properly. Homeostasis can be split into two categories, Negative feedback and Positive feedback. In the Negative feedback process the control centre will send signals to shut off, or reduce the intensity of the original stimulus, for example when your body heat increases through running, negative feedback is delivered to maintain a moderate body temperature. The cells of the control centre are no longer stimulated by the sensory nerve endings meaning the effects are negated.
Positive feedback heads in the same direction as the original stimulus. For example a person wanting to pass urine but not having a place to do so would have an increasing urge as time passed, this would continue until the stimulus was no longer present. Once urine had been passed the stimulus is no longer present and the urge has passed.
Tucker, L 2005 Anatomy & Physiology Cambridge Holistic Therapy Books Berne, RM 1993 Physiology Missouri Mosby