Endothelial cells are the structural basis of the blood brain barrier and are joined by tight cellular junctions. These junctions are impermeable to proteins and also restrict the passage of non-lipid soluble molecules. Within the BBB, most molecules use carrier systems. The properties of the BBB are induced and probably maintained by molecules secreted by [[#Astrocytes|astrocytes]]. The BBB prevents circulating antibodies reaching the CNS and thus is a component of the immunological privilege manifest by the CNS. The BBB is not considered to affect the movement of inflammatory cells into the CNS; activated lymphocytes can enter the normal CNS. | Endothelial cells are the structural basis of the blood brain barrier and are joined by tight cellular junctions. These junctions are impermeable to proteins and also restrict the passage of non-lipid soluble molecules. Within the BBB, most molecules use carrier systems. The properties of the BBB are induced and probably maintained by molecules secreted by [[#Astrocytes|astrocytes]]. The BBB prevents circulating antibodies reaching the CNS and thus is a component of the immunological privilege manifest by the CNS. The BBB is not considered to affect the movement of inflammatory cells into the CNS; activated lymphocytes can enter the normal CNS. |