This exhibit features an enlarged detail of a brain cross section to highlight the layers of surrounding tissue. Skin, subcutaneous fat, galea aponeurotica, and pericranium cover the outer skull. The skull interior is lined with endocranium and dura mater. The dura mater is a tough, membranous sac that protects the brain. It also contains cerebrospinal fluid and the venous sinuses. Beneath the dura lies the leptomeninges (arachnoid mater and pia mater), which cover the brain, and also contain cerebrospinal fluid. Cerebral arteries travel through the subdural spaces and supply blood to the brain tissues.