Explain the concept of physiological stress. Explain the concept of homeostasis. The four components of a negative feedback loop are the stimulus, the sensor, the control center, and the effector. Tell the role of each component in the negative feedback loop. Draw a negative feedback loop showing the relationship between each component of the loop. Explain what would happen if secretion of a body chemical controlled by a negative feedback system became too great. Tell which two human body organ systems are responsible for homeostatic control. Explain the reason maintenance of homeostasis is essential for living organisms. Explain the reason positive feedback mechanisms, while useful, are NOT homeostatic.