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.
Earthrise, the first picture taken of planet Earth by people orbiting the moon. This shot was captured by Apollo 8 astronaut Bill Anders on December 24, 1968, as his spacecraft became the first to fly around the moon.Credit: NASA.he photo he picked is called Earth From Mars, which was taken by NASA's Mars Exploration Rover Spirit on March 8, 2004. It was the first image of Earth seen from the surface of a planet beyond the moon.