Читать книгу Understanding Anatomy and Physiology in Nursing - John Knight - Страница 61

All homeostatic processes that rely on negative feedback must have the following elements.

 A stimulus: this is the trigger that causes the variable to deviate from its set point, e.g. moving to a cold environment will lower the core temperature.

 A sensor: to detect deviations from the set point, e.g. the core and skin thermoreceptors that measure temperature changes.

 A control centre: to decide how to bring the variable back towards its set point, i.e. the thermoregulatory centre of the hypothalamus.

 Effector organs and tissues: to effect the physiological changes necessary to bring the variable back towards its set point, e.g. the sweat glands and blood vessels in the dermis of the skin that help control heat loss and retention.