brain, spinal cord, and nerve disorders
Brain
Meninges
Both the brain and spinal cord are covered by 3 layers of tissue (meninges) that protect them: Within the skull, the brain is covered by three layers of tissue called the meninges: Dura mater (outer layer) Arachnoid mater (middle layer) Pia mater (inner layer) Between the arachnoid membrane and pia mater is the subarachnoid space. This space contains cerebrospinal fluid, which flows through the meninges, fills the spaces within the brain, and helps cushion the brain and spinal cord. The thinpia materis the innermost layer, which adheres to the brain and spinal cord. The delicate, spider web–likearachnoid materis the middle layer. The leatherydura materis the outermost and toughest layer. The space between the arachnoid mater and the pia mater (the subarachnoid space) is a channel for cerebrospinal fluid, which helps protect the brain and Spinal Cord . Cerebrospinal fluidhelps to cushion the brain against sudden jarring and minor injury and also to remove waste products from the brain. The cerebrospinal fluid is contained in a network of spaces within the brain called ventricles. The cerebrospinal fluid is formed by specialized cells that line the ventricles, and it enters the brain along the outside of blood vessels and flows over the surface of the brain between the meninges. The fluid is taken up by support cells (glial cells) and distributed throughout the brain, filling internal spaces within the brain (the 4 cerebral ventricles). Eventually, the fluid leaves the brain to enter the body's blood vessels. As the cerebrospinal fluid flows through the brain, it removes discarded proteins and other waste products from the brain tissue. This removal process occurs mainly when people are sleeping, which highlights the importance of sleep. The brain and its meninges are contained in a tough, bony protective structure, the skull. The Spinal Cord connects to the brain at the base of the brain stem. 