In: Anatomy and Physiology
Neurons have special cell parts called dendrites and axons.Dendrites bring electrical signals to the cells body and axon take information away from the cell body.Neurons communicate each other through an electrochemical process.
The Non self materials are- Antigens ,which is prevented by Blood brain barrier(BBB),which act as as a semipermeable membrane. so antigens has to cross the BBB to infect the neurons of the brain.
BBB is a semipermeable membrane separating the blood from cerebrospinal fluid and constituting a barrier to the passage of cells,particles and large molecules.It mostly protects the brain from foreign substances in the blood that may injure the brain. Protects the brain from hormones and neurotransmitters in the rest of the body.Maintains a constant environment for the brain.
Its main purpose is to protect against circulating toxins or pathogens that could cause brain infection,while at the same time allowing vital nutrients to reach the brain .its a highly selective semipermeable border of endothelial cells that prevents solute in circulating the blood from non selectively crossing into extracellula fluid of the central nervous system where neurons reside.