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.
How does Earth keep its orbit around the Sun and not come closer to the Sun. Answer 1: The Earth is always being pulled towards the Sun by gravity. If the Earth were stationary compared to the Sun, it would fall into the sun under the force of gravity.However the Earth is actually moving sideways compared to the center of the Sun at 3 km/second (~2 miles/second).ow does Earth keep its orbit around the Sun and not come closer to the Sun. Answer 1: The Earth is always being pulled towards the Sun by gravity. If the Earth were stationary compared to the Sun, it would fall into the sun under the force of gravity.