This process is an example of negative feedback. As for the control of the breathing rate, the medulla also controls the heart rate. The set process for the regulation of the heart rate is rather complex and is as follows.As an individual exercises, special receptors located within the muscles send impulses to the medulla.lood glucose is another contributing factor to homeostasis. The blood glucose concentration in the blood is vital to the functioning of cells within the body and is controlled by a number of internal structures and external influence (food and drink).