In the central nervous system, there are three different layers that cover the spinal cord and brain. These are called the meninges, and their three levels consist of the: pia, arachnoid, and dura mater. Bone is situated above these layers, followed by periosteum (a fibrous membrane that covers bone) and skin.The dura mater is the top layer of the meninges, lying beneath the bone tissue.This material at times opens into sinus cavities (spaces) located around the skull.he dura mater is the top layer of the meninges, lying beneath the bone tissue. This material at times opens into sinus cavities (spaces) located around the skull.
Planet Earth Making Mountains Planet Earth filmmakers came out in the rugged mountains of Nepal in hopes of filming the elusive snow leopard for the Mountains episode. 01:51.
For the 2006 BBC TV series, see Planet Earth (TV series) . The cover of Planet Earth, the companion book to the series by Jonathan Weiner published in 1986. Planet Earth is a seven-episode 1986 PBS television documentary series focusing on the Earth, narrated by Richard Kiley. Planet Earth explores geoscience and how discoveries of the early and mid-1980s were revolutionizing mankind's understanding of the Earth's past, present, and future.