Neurobiology is the scientific study of the nervous system. It is a multidisciplinary branch of biology, which deals with the anatomy, biochemistry, molecular biology, and physiology of neurons and neural circuits. It also draws upon other fields, with the most obvious being pharmacology, psychology, and medicine. The scope of neuroscience has broadened over time to include different approaches used to study the molecular, cellular, developmental, structural, functional, evolutionary, computational, psychosocial and medical aspects of the nervous system.