Fatty Change A toxic cellular change that occurs with severe cellular injury.  The cell has become damaged and is unable to adequately metabolize fat, resulting in development of small vacuoles of fat that accumulate and become dispersed within the cytoplasm.  It is usually observed in the liver. Feed Back Mechanism A part of the homeostasis in which the body regulates the degree of response to a stimulus.  A negative feed back depresses the stimulus to shut off or reduce the effector response whereas a positive feed back has the effect of increasing the effector response.