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.
Snapchat, meanwhile, sees the âPlanet Earth IIâ show as content designed to live on its own, a way to refashion a popular TV franchise for its digital audience. The service is running ads in the show, with Goldman Sachs among the sponsors for the first episode. The six-episode Snapchat show will premiere on Feb. 17, the day before the television premiere of the âPlanet Earth IIâ nature documentary series in the U.S. (on BBC America) and Canada (on BBC Earth) on Feb. 18.