Definition of opacity for English Language Learners. : 1  the quality of a material that does not allow light to pass through it : the quality of being opaque. : 2  the quality of being difficult to understand or explain.
Research has shown that this is not true, and that brain cells can and do regenerate, especially in the areas related to learning, decision-making, visual recognition, and the way people perceive objects in space.weet. For a long time, scientists thought that it was impossible for brain cells to regenerate because they assumed that any new cells would disrupt the order of the brain.
The healthy human brain contains tens of billions of neuronsâspecialized cells that process and transmit information via electrical and chemical signals. They send messages between different parts of the brain, and from the brain to the muscles and organs of the body. Alzheimerâs disease disrupts this communication among neurons, resulting in loss of function and cell death. Key Biological Processes in the Brain Most neurons have three basic parts: a cell body, multiple dendrites, and an axon. 1  The cell body contains the nucleus, which houses the genetic blueprint that directs and regulates the cellâs activities. 2  Dendrites are branch-like structures that extend from the cell body and collect information from other neurons.