Full regulation center is directly connected with hearing management. When sense of smell sensor probes the aromatic molecules in the air, directly transmit to the full regulation center through smell tube. The brain full central pivot receives the quantity of the fragrance transferred by smell sensor and the number of taste transferred by taste sensors to detect the intake of relevant food, so as to detect degree of full feelings. In other words, the brain uses aromatic molecules to operate its full signal. Once the full central receives enough aroma molecules, it will send out a signal: "you eat enough, you are full". At this time, you will feel very full and no longer want to eat. People have a keen sense of smell, inside the person's nasal cavity there are a great deal of olfactory receptors. Smell receptors are directly connected with brain center, through the nervous. Thus, people's sense of smell response is direct and rapid. When we smell bad smells, we will hold our breath and reduce the inhalation of smelly gases. And when we smell good gas, we will deepen our breath, inhale more.