Homeostasis can simply be described as the maintenance of a constant internal environment. Human bodies must get rid of accumulating toxic substances which can harm the body. Things like sugar concentration in the blood and body temmperature also have to be kept within narrow ranges to prevent harmful effect. The nervous system and hormones are responsible for maintaining homeostatis. Lets look at this with an example: how blood sugar level maintained The blood glucose level is monitored and controlled by the pancreas. When there is too much glucose in the blood, the pancreas releases insulin, a hormone, which causes glucose to be moved from the blood to the cells. When there is too little sugar, a second hormone called glucagon is produced. This causes glycogen to be converted to glucose and released in the blood. Thus, blood glucose levels are maintained within a narrow range.