The blood-brain barrier. I. Histology. Physiology. Embryology. Transport

The concept of blood-brain barrier (bbb) arose in the beginning of the 20th century after report that the dyes injected intravenously did not appear in the brain. The idea and definition of bbb has been changed many times since then. We present current opinion concerning bbb, its histology, embryology, ultrastructure and function on the ground of a review of the recent literature.