What departments does the human brain consist of, how is the white and gray matter distributed, the meaning

What departments does the human brain consist of, how is the white and gray matter distributed, the meaning of the convolutions of the cerebral hemispheres?

The human brain consists of three sections:
-Stem (medulla oblongata, bridge, diencephalon)
-Cerebellum
-Forebrain (cerebral hemispheres)
The gray matter is a thin, 3-4 mm thick, surface layer – the cortex of the hemispheres. There is a white matter under the bark. In the thickness of the white matter, there are large accumulations of gray matter – nerve centers (subcortical nuclei) and cavities – lateral ventricles.
The convolutions are the folds of the cerebral cortex, and the grooves between them are the grooves. This structure allows you to significantly increase the surface of the brain, the surface of the cerebral cortex.
Large grooves divide the hemispheres into 4 lobes: frontal, parietal, occipital and temporal.