Choroid plexus: Definition, Function, Structures, Diagram, Facts, FAQs

What Is Choroid Plexus?

The choroid plexus is a collection of cells located within the ventricles of the brain, especially inside the lateral, third, and fourth ventricles. It comprises ependymal cells, blood vessels, and connective tissue and forms the CSF. The choroid plexus filters blood for the production of CSF, which later goes into the brain and spinal cord, cushioning, nourishing, and clearing waste products. It forms a part of the maintenance of the internal environment of the brain and helps in the sustenance of neural health for overall correct functionality of the central nervous system.

Anatomy Of The Choroid Plexus

The choroid plexus is a structure inside the ventricles of the brain that accounts for the largest proportion of cerebrospinal fluid production. It can be found in all parts of the ventricles inside the brain, namely the lateral, third, and fourth ventricles.

Location and Structure Of Choroid Plexus

• The choroid plexus lies in all four ventricles of the brain, namely, two lateral ventricles, the third ventricle, and the fourth ventricle.

• The location extends from the lateral ventricles through the interventricular foramina into the third ventricle, then goes on through the cerebral aqueduct into the fourth ventricle.

• The choroid plexus is composed of an epithelium layer, connective tissue, and a rich network of blood vessels.

• The epithelium is lined by cuboidal choroidal epithelial cells that secrete CSF.

• The choroidal epithelial cells are underlaid by thin stroma connective tissue under the epithelium to which blood vessels that supply the plexus are anchored.

• These blood vessels are fenestrated and allow the filtration of blood plasma into the ventricles to form CSF.

Histology

• The choroid plexus is very defined and complicated when viewed microscopically.

• These epithelial cells, otherwise named ependymal cells, appear cuboidal to columnar and cover the connective tissue core underlying them continuously.

• The major cells of the choroid plexus include epithelial cells, also called choroidal epithelial cells or ependymal cells.

• These cells have microvilli and cilia on the apical surface that will aid in the movement and secretion of CSF.

• Also, under the stromal connective tissue, there are several kinds of support cells and blood vessels to help in the exchange of materials for CSF production.

Functions Of The Choroid Plexus

The choroid plexus is the part of the brain that is responsible for the significant production of CSF and the maintenance of the blood-CSF barrier.

Cerebrospinal Fluid (CSF) Production

• It is produced by the choroid plexus through the process involving filtration of blood plasma.

• This makes the blood vessels within the choroid plexus fenestrated, and as such, plasma passes through them into the stroma.

• At this point, the choroidal epithelial cells secrete this filtrate into the ventricles as CSF, enriched with essential ions, nutrients, and other substances.

• It regulates the volume and composition of the CSF.

• It maintains the volume of the CSF with the proper balance of the electrolytes, glucose, and other essential molecules.

• With this, it controls the intracranial pressure and gives the best environment for the proper functioning of the neurons.

Blood-CSF Barrier

• The blood-CSF barrier derives from tight junctions between the choroidal epithelial cells.

• These junctions hamper free diffusion into the CSF from the blood for large molecules and pathogens but allow, in a selective manner, the majority of essential nutrients and ions.

Importance In Protecting The Brain

• Blood-CSF prevents most of the noxious chemicals and pathogenic agents from the blood into the CSF and eventually into the CNS.

• It becomes rather important to maintain such an optimal environment to protect the safe and stable operation of the brain.

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