Choroid plexus

Choroid plexus can be found in all of the four ventricles in the brain, it produces and secretes most of the cerebrospinal fluid (CSF) in the brain. Active transport of substances into and out of the CSF.

The tissue includes loose connective tissue (pia mater) and capillaries surrounded by a layer of specialized ependymal cells (cuboidal epithelial cells). The epithelial layer lining the ventricular system is continuous with the choroid plexus epithelial layer. However, unlike ependymal cells of the ventricle wall, the choroid plexus has tight junctions and functions as an important part of the blood-brain-barrier.

The choroid plexus includes numerous folds and villi, as well as microvilli that increase the cell surface.