Homeostasis is the regulation and maintenance of the internal environment. There is a narrow range of conditions within the body to function normally, and homeostasis keeps the internal environment within that narrow range. 

The internal control systems in our bodies that help maintain homeostasis 

• use sensors to gather data
• a control center receives the data and sends a message
• a communication system delivers messages to target organs or tissues
• the target organs or tissues respond to change

Most functions in the body are regulated by negative feedback loops. Feedback is information from sensors. Negative feedback loops counteract changes in the body that move away from 'normal'. An example of negative feedback is your body will shiver if the temperature drops, to bring up the temperature. Positive feedback increases the rate of change. An example of positive feedback occurs when you cut your finger, the rate of change in clotting factors in the blood increases, until the cut is sealed.