Median (profile) section through the centre of a whole human brain. The heavily folded and grooved cerbral cortex (the outer grey matter of the brain) appears unsectioned. The feathery sectioned structure at bottom right is the cerebellum, the centre of muscular coordination; to left is the brainstem (white, consisting of the bulbous pons & medulla oblongata), which contains centres for control of breathing & heart functions. The spinal cord extends below the brainstem. The large curved central structure (roughly white) is the corpus callosum, which connects the two cerebral hemispheres that comprise the cerebrum.