Neurobiology is the study of cells of the nervous system and the organization of these cells into functional circuits that process information and mediate behavior.
It is a subdiscipline of both biology and neuroscience. Neurobiology differs from neuroscience, a much broader field that is concerned with any scientific study of the nervous system.
Neurons are cells that are specialized to receive, propagate, and transmit electrochemical impulses. In the human brain alone, there are over a hundred billion neurons. Neurons are diverse with respect to morphology and function.