choroid plexus

anatomy

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

June 24, 2026

Quick Summary

The choroid plexus is a network of blood vessels within the brain's ventricles, specifically in the walls of the lateral ventricles. It is lined by ependymal cells, which are a type of neuroglia derived from embryonic neuroectoderm.1

The primary function of the choroid plexus is the production of cerebrospinal fluid (CSF). Ependymal cells selectively absorb water and other molecules from the blood and secrete them into the ventricles as CSF. This fluid circulates within the brain's ventricular system and the central canal of the spinal cord, providing nutrients and removing waste products. The ependymal cells surrounding the choroid plexus have tight junctions that prevent harmful substances from entering the CSF.123

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

prenatal development
Brain
…and myelencephalon differentiate the vascular choroid plexuses—including portions of the pia mater, or innermost brain covering, that project into the ventricles, or cavities, of the brain. The choroid plexuses secrete cerebrospinal fluid.
Read More
…and myelencephalon differentiate the vascular choroid plexuses—including portions of the pia mater, or innermost brain covering, that project into the ventricles, or cavities, of the brain. The choroid plexuses secrete cerebrospinal fluid.
Read More

ependymal cell
…epithelial layer that surrounds the choroid plexus, a network of blood vessels located in the walls of the lateral ventricles (the two largest ventricles, which occur as a pair in the cerebral hemispheres). Ependymal cells, similar to all other neuroglia, are derived from a layer of embryonic tissue known as…
Read More
…epithelial layer that surrounds the choroid plexus, a network of blood vessels located in the walls of the lateral ventricles (the two largest ventricles, which occur as a pair in the cerebral hemispheres). Ependymal cells, similar to all other neuroglia, are derived from a layer of embryonic tissue known as…
Read More

human nervous system
Cerebral ventricles
…it is secreted by the choroid plexus, a collection of blood vessels in the walls of the lateral ventricles. The fluid drains via interventricular foramina, or openings, into a slitlike third ventricle, which, situated along the midline of the brain, separates the symmetrical halves of the thalamus and hypothalamus. From…
Read More
…it is secreted by the choroid plexus, a collection of blood vessels in the walls of the lateral ventricles. The fluid drains via interventricular foramina, or openings, into a slitlike third ventricle, which, situated along the midline of the brain, separates the symmetrical halves of the thalamus and hypothalamus. From…
Read More