The blood-brain barrier is
formed by which of the following?
A. Fenestrations between brain capillary endothelial cells B. Occluding junctions between brain capillary endothelial cells C. Astrocytic foot processes surrounding blood vessels entering the brain parenchyma D. The basement membrane associated with the glia limitans E. Microglial activity
Occluding junctions between brain capillary endothelial cells -the blood-brain barrier is formed primarily by occluding junctions (zonulae occludentes) between endothelial cells that compose the lining of brain capillaries. the capillary endothelium is nonfenestrated, which also adds to the barrier. in addition, astrocytes form foot processes around the brain capillaries. surrounding the cns is a basement membrane with a lining of astrocyte foot processes; this forms the glia limitans, which also contributes to the integrity of the blood-brain barrier. oligodendrocytes function in myelination of cns axons. microglia function as brain macrophages and are involved in antigen presentation and phagocytosis.