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.
The blood-brain barrier is made up of very small blood vessels (capillaries) that are lined with thin, flat endothelial cells. In other parts of the body, endothelial cells have small spaces between them that allow substances to move in and out of the capillary so they can reach other cells and tissues.In the brain, the endothelial cells are packed tightly together so substances cannot pass out of the bloodstream into the brain.n other parts of the body, endothelial cells have small spaces between them that allow substances to move in and out of the capillary so they can reach other cells and tissues. In the brain, the endothelial cells are packed tightly together so substances cannot pass out of the bloodstream into the brain.