Homeostatic control system and components feedback mechanism 

mechanism: 

for example, sweat glands work as effectors by releasing sweat to lower body temperature in the body; and hepatocytes of the liver release glucose to increase blood glucose levels.

feedback mechanism: 

The homeostasis control system is a signal directed mechanism which work in a feedback loop and can occur at organ, cellular or molecular level.

Negative feedback mechanism

Most control system maintain homeostasis by negative feedback mechanism. it keep the set point of the physiological states constant in the body by reversing the change in physiological variable, if they are outside the normal range. for example, the enzymatic reaction inhibits the first step of the same reaction.

The mechanism of homeostatic control system is called the negative feedback loop. regulation of body 

temperature by the negative feedback loop in which increase in the body temperature act as the stimulus which increase in the nerve cells in the skin and brain. the sensors send the signal to the temperature regulatory center in the brain. hypothalamus which finally sends signal to effectors (sweat glands) that release a chemical messenger  (sweat) to shutoff the change in the stimulus in order to normalize the exceeded temperature of the body.

Positive feedback mechanism

positive feedback mechanism instead of reversing the change, increases the change in the body's physiological condition. for example during childbirth the first contractions of labor (stimulus) pushes the baby toward the cervix and stimulate the stretch receptors. the brain (control center) receives the signal and oxytocin hormone is released from the pituitary gland. oxytocin causes stronger contractions of the smooth muscles (effectors) pushing the baby further down. this cause even greater stretching of the cervix sending more signals the cycle goes on till the baby is born. the cessations of the stretching of the cervix stops the release of oxytocin. another example is the platelet aggregation and accumulation in response to an injury.