Messages enter a cell through its dendrites and travel on through the cell. When a message reaches the end of an axon, certain chemicals are released that move across the gap between the axon and the next cell s dendrites. These chemicals allow the dendrites to receive the message. This occurs because the type of the information stored on neurons in a particular area of the brain determines what function that area will have. Having some of your neurons die naturally occurs with aging and doesn t present a major problem.
Neurons can also die due to brain injury or disease.
Sometimes older people develop a disease called Dementia in which lots of their neurons die. When this happens, their brain doesn t function properly. Alzheimer s disease is a type of dementia. As neurons in certain areas of the brain die, the function of that area of the brain is affected. I changed around, a little bit, the script for the 3-D brain and the nervous system stuff from what Nancy had written please check this content for correctness.