THE BRAIN FROM TOP TO BOTTOM. The Whole Brain Atlas. Brain Atlas - Introduction. The central nervous system (CNS) consists of the brain and the spinal cord, immersed in the cerebrospinal fluid (CSF).
Weighing about 3 pounds (1.4 kilograms), the brain consists of three main structures: the cerebrum, the cerebellum and the brainstem. Cerebrum - divided into two hemispheres (left and right), each consists of four lobes (frontal, parietal, occipital and temporal).