Human Brain (Norm Barker)

Photograph by

Medical Group

About this image

The brain is the center of the nervous system in many species, including humans. It contains roughly 100 billion neurons that are connected to each other in an elaborate matrix with up to 10,000 connections for each neuron. Neurons communicate with one another by means of long fibers called dendrites and axons, which carry electrical signals to and from other regions of the brain or nervous system. In fact, methods of observation such as an electro-encephalogram (EEG) record these electrical signals, and tell us that the communications among neurons is highly organized. This image at is an example of a normal human brain when seen under a microscope. The large round rust colored cells are the neurons, and the tangles of black fibers are the dendrites and axons that connect each neuron to each other and to other neurons in different parts of the brain or body. The image illustrates two individual neurons isolated from brain tissue. In this instance, the axons and dendrites that extend from a single cell are better appreciated.