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.
Well, Earth is located in the universe in the Virgo Supercluster of galaxies. A supercluster is a group of galaxies held together by gravity. Within this supercluster we are in a smaller group of galaxies called the Local Group. Earth is in the second largest galaxy of the Local Group-a galaxy called the Milky Way. The Milky Way is a large spiral galaxy. Earth is located in one of the spiral arms of the Milky Way (called the Orion Arm) which lies about two-thirds of the way out from the center of the Galaxy.