Human Physiology explains about the science of mechanism behind the body works and has become a fundamental discipline of modern medicine. It analyzes the interaction of molecules, cells, tissues and organs, and emphasizes the concept of making up the whole body. The new finding came into existence that autophagy (eating own cell) is an essential component in a neuroendocrine pathway which allows sensory neurons and nutrient levels to work together to influence lifespan. It also reduces the insulin growth factor signaling pathway, by which the cells communicate with their physiologic environment.