Morphological changes in cerebrospinal fluid production.

The ventricular system and subarachnoid space are filled with cerebrospinal fluid, which plays a key role in the nervous system. This fluid is produced by the choroid plexus, an organ rich in ion transporters that precisely control the transport of specific ions into the cerebrospinal fluid thanks to tight junctions between the plexus cells; these prevent the passage of substances other than the transporters, thus allowing for precise control of the fluid composition. Cerebrospinal fluid production is based on a network of interrelationships between specific ion flows enabled by the numerous transporters. The fluid is cleaned and resorbed by the glymphatic system via multiple absorption pathways. Maintaining proper cerebrospinal fluid parameters is extremely important for proper brain function. Considering the fragility of the brain, even small fluctuations in cerebrospinal fluid composition can impair its condition. Therefore, to understand the nervous system, it is important to have thorough knowledge of the production, transport, and resorption mechanisms of cerebrospinal fluid. The aim of this paper was to summarise the current state of knowledge about the mechanisms of production, pathways of absorption, and physiological values, of cerebrospinal fluid parameters. We also discuss the role of the glymphatic system in maintaining fluid homeostasis, and the changes resulting from its dysfunction as a result of trauma.