Choroid Plexus

Ependymal Cells
This is a colored scanning electron micrograph (SEM) of the lining of the brain, showing ependymal cells (yellow) and ciliary hairs (green). Ependymal cells are a type of neuroglia (glial cells) that surround the choroid plexus, line the ventricles of the brain, and produce cerebrospinal fluid (CSF). Credit: STEVE GSCHMEISSNER/Science Photo Library/Getty Images

The choroid plexus is a network of capillaries and specialized ependymal cells that is found in the cerebral ventricles. The choroid plexus serves two important functions in the body. It produces cerebrospinal fluid and helps to provide a barrier, which protects the brain and other central nervous system tissue from toxins.

Choroid Plexus: Location

The choroid plexus is located in the ventricular system.

This series of connecting hollow spaces house and circulate cerebrospinal fluid. Choroid plexus structures are found in certain locations within both lateral ventricles, as well as within the third ventricle and fourth ventricle of the brain. The choroid plexus resides within the meninges, the membrane lining that covers and protects the central nervous system. The meninges is composed of three layers known as the dura mater, arachnoid mater, and pia mater. The choroid plexus can be found in the innermost layer of the meninges, the pia mater. The pia mater membrane contacts and directly covers the cerebral cortex and spinal cord.

Choroid Plexus: Structure

The choroid plexus is composed of blood vessels and specialized epithelial tissue called ependyma. Ependymal cells contain hair-like projections called cilia and form a tissue layer that encases the choroid plexus. Ependymal cells also line the cerebral ventricles and spinal cord central canal.

Ependymal cells are a type of nervous tissue cell called neuroglia that produce cerebrospinal fluid.

Choroid Plexus: Function

Choroid plexus ependymal cells are vital for the production of cerebrospinal fluid. Ependyma tissue surrounds the capillaries of the choroid plexus separating them from the cerebral ventricles.

Ependymal cells filter water and other substances from capillary blood and transport them across the ependymal layer into the brain ventricles. This clear fluid is the cerebrospinal fluid that fills the cavities of the cerebral ventricles, the central canal of the spinal cord, and the subarachnoid space of the meninges.

The choroid plexus along with the arachnoid membrane of the meninges also form a barrier between the blood and the cerebrospinal fluid. This barrier is called the blood–cerebrospinal fluid barrier and serves to prevent harmful substances in the blood from entering the cerebrospinal fluid and causing damage to central nervous system structures.