ASTROCYTES ANATOMYAstrocytes are quite large. They are stellate cells that have numerous cytoplasmic processes radiating out from the cell. Within the central nervous system the astrocytes are the most plentiful. In specific area of brain tissue, the astrocytes create 90% of the nervous tissue. As opposed to most of the body’s organs, the capillaries within the brain lack pores between the endothelial cells.
ASTROCYTES FUNCTIONSThus, the molecules of wastes must be removed from the brain’s capillaries via transport, meaning endocytosis and exocytosis. Astrocytes in the brain are equipped with vascular processes which surrounds the majority of the brain’s outer layer of capillaries. Prior entering the brain, the molecules from the blood stream must pass through both the astrocytes and the endothelial cells.
This protection, known as the blood brain barrier, prevents unwanted molecules from entering the brain. This system is known to be highly selective and every molecule permitted to pass into the brain must serve a functional purpose.