PHYSIOLOGY OF THE CSF

Abstract

SummaryA certain production of CSF occurs at the site of the choroid plexus. This CSF differs in composition from a pure plasma dia‐lysate and is thus probably formed by a secretory or other active process from the epithelium of the plexus. At the same time, however, certain substances, especially water, are in rapid exchange with the extracellular tissue of the brain and spinal cord.Reabsorption of the CSF occurs partly via arachnoidal villi and Pacchionian bodies to the cranial venous sinuses, partly via intrathecal capillaries and veins and finally to some extent by way of lymphatics via the perineural spaces.The protein in the CSF probably consists of serum protein, that has entered the CSF space. Protein is normally not formed within the central nervous system but may be under certain pathologic conditions. Normally, the serum protein enters the CSF space in two ways: pardy via meningeal vessels above all of finely dispersed proteins especially albumin, and partly via the choroid plexus either by passage via intercellular leaks in the plexus epithelium or also through secretion or some other active process. The CSF formed by the choroid plexus is relatively poor in protein and has an electrophoretic pattern, that differs more from that of serum protein than does CSF fluid from other parts of the CSF space.The reabsorption of the CSF protein occurs mainly directly to the blood stream, either via arachnoidal villi to the cranial venous sinuses or via intrathecal capillaries and veins. Reabsorption of protein via lymphatics is probably insignificant.