The control of blood sugar (glucose) by insulin, is another pretty good example of a negative feedback mechanism. When your blood sugar rises, receptors in your body senses a change. In turn, the control center (pancreas) secrets the insulin into the blood which can effectively lower you blood sugar levels.
Homeostasis is maintained by negative feedback loops within the organism. In contrast, positive feeback loops push the oganism further out of homeostasis, but may be necessary for life to occur.
Negative feedback loops occur in your body through its own internal controller for maintaing tempurature, pH, hormone levels, blood sugar and other internal variable levels at homeostasis, which is the optimal internal state at which your body operates best.
Hope this helps you.