A 2-day-old premature

newborn develops a severe form of neonatal jaundice, which unfortunately has a

serious complication, the so-called kernicterus. It is essentially damage of

the brain nuclei, especially the basal ganglia, by a high concentration of a

compound known as unconjugated bilirubin, which causes the aforementioned

jaundice. This condition is caused by the immaturity of the blood-brain

barrier, which is not yet able to fulfill its function as a barrier, and

bilirubin reaches the nervous tissue through it. In older children and adults,

this condition no longer occurs thanks to a mature and functional blood-brain

barrier. What parts make up this barrier?