Type O negative blood (red cells) can be transfused to patients of all blood types. It is always in great demand and often in short supply. Type AB positive plasma can be transfused to patients of all other blood types. AB plasma is also usually in short supply.
Blood-brain barrier. A blockade of cells separating the circulating blood from elements of the central nervous system (CNS); it acts as a filter, preventing many substances from entering the central nervous system.
2. Poison Defense: Some glial cells support the role of âblood brain barrier.â They will simply block most harmful substances from ever reaching the neuron. (Without this barrier, most molecules in the blood would become deadly poisons!).