Abstract
We begin with the introduction of the general biophysics relevant concepts for the nervous system that will be discussed in more detail in the next chapters of the book. The first step deals with the neuron: the fundamental morphological and functional unit of the human nervous system (HNS). It is known that HNS (i.e., central nervous system, CNS and peripheral nervous system, PNS) consist of about 86 billion neurons (Azevedo et al. 2009; Herculano-Houzel 2009) without taking into account the glial cells that outnumber neurons by tenfold, and astrocytes. However, it is interesting to note that astronomers estimate the number of stars in the Milky Way as being about 400 billion, that is, only five times the number of HNS neurons! It seems that glia has only the role to insulate, support, and nourish the neighbor neurons, construct axon myelin, repair brain injury, although this simple view merely reflects our ignorance about glial function (Bear et al. 2001).
