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.
Photograph courtesy NASA/Lunar Orbiter 1. This photo reveals the first view of Earth from the moon, taken by Lunar Orbiter 1 on August 23, 1966. Shot from a distance of about 236,000 miles (380,000 kilometers), this image shows half of Earth, from Istanbul to Cape Town and areas east, shrouded in night.hotograph courtesy NASA Johnson Space Center. This famous Blue Marble shot represents the first photograph in which Earth is in full view. The picture was taken on December 7, 1972, as the Apollo 17 crew left Earthâs orbit for the moon.