An imaginary line that runs the length of the spinal cord to the front of the brain. Structures that are on the same side of the midline. Structures that are on opposite sides of the midline. An imaginary line that divides us into 2 halves. Allows us to view brain structures from side. Composed of leather like tissue that follows the outlines of the skull bones: arachnoid layer. In between arachnoid layer and pia mater is subarachnoid space. Dura mater and pia mater cover nerves that exit the brain and spinal cord (pns). Meningitis- infection of the meninges by various viruses and bacteria. Csf is secreted within the ventricles (hollow spaces in brain). Ventricles are lined with choroid plexus, which converts material from blood supply to csf (similar in composition to clear blood plasma). Csf cushions the brain from bumps and prevents neurons from responding to pressure on the brain.