The Choroid Plexus—CSF Nexus

Cerebrospinal fluid (CSF) has a major impact on the volume and composition of the interstitial fluid that envelops the neurons. Choroid plexus tissue in the four ventricles is the source of up to 80–90% of this actively secreted transcellular CSF, which is derived from the carotid and vertebral blood supplies. As the CSF flows from its choroidal origins to more distal sites, it comes into contact with other membranes that encompass brain tissue: the ependyma, which lines the ventricular system, and the pia-glia and arachnoid membranes which border the subarachnoid space (SAS). As a result, the composition of the continually flowing CSF, and of the adjacent brain interstitium, is progressively modified by bidirectional exchanges of water, ions, and proteins at these transport interfaces. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.