Unlike Alzheimer's disease, which shrinks the hippocampus causing progressive memory loss, white matter disease is a more diffuse mind-robbing condition that targets small blood vessels deep within the brain's white matter. The disease hardens the tiny arteries, gradually restricting nutrients to white matter -- the connections between brain regions involved in executive abilities such as planning, organizing, problem-solving, and attention.
Parts of the Nervous System. The center of the nervous system is the brain. The brain takes in what your eyes see and ears hear, and if you decide that you want to move around, your brain tells your muscles to do it. Your brain makes your muscles move by sending tiny electrical signals to them through your nerves. Peripheral nervous system (PNS): a part of the nervous system which includes all the nerves outside of the brain and spinal cord. 2  Sympathetic nervous system: The part of your nervous system that unconsciously controls your organs and glands when you're excited or frightened.
Retina The retina is the area at the back of the eye that receives the refined, visual message from the front of the eye, and it transmits that visual message to the brain using electrical signals. Sclera The sclera is the white part of the eye, and its main function is to provide strength, structure, and protection for the eye. The sclera contains blood vessels that can tell an eye doctor a lot about the state of your overall health.