Homeostasis is the process by which every living thing makes continual adjustments to keep itself in a stable condition and function to the best of its ability. It is a self-regulating activity, with pre-set limits. For example, the levels of blood sugar is regulated by the amount of insulin that the pancrease secretes, if you just ate a meal then your body would secretes insulin by itself the adjust and compensate.
The belief in the self regulation capasity of the body is very ancient, and in the western medical tradition can be traced back to Hippocrates. Dr. Still reaffirmed this belief even before the discovery of the law of homeostatis.
The homeostatic mechanism is important when our body functions are disrupted since it will restore the natural balance. This occurs in every part of our body since every physical structure has its own memory.