What is Choroid plexus?
It is a multi-lobed vascular structure of the pia mater that projects into the ventricles of the brain. The term is derived from the Greek words “khorion” meaning “membrane enclosing the fetus” and “plexus” referring to “network”.
Choroid plexus Insertion
It inserts into the side of the lateral ventricle through a cleft called choroid fissure.
Choroid plexus Location
The nerve complex can be found in the ventricular system, a communicating cavity within the brain. However, the cerebral aqueduct, occipital horn of the lateral ventricle, and the frontal horn of the lateral ventricle are devoid of the vascular plexus. It can be clearly located in the superior region of the inferior horn of the lateral ventricles. It runs up the boundary to join the lower ventricles. The rich network of blood vessels traverses the interventricular foramen and merges with the third ventricle at the top. It is also found in the fourth ventricle.
Choroid plexus Anatomy
The villous structure comprises of multiple capillaries that are interspersed by choroid epithelial cells. Cerebral fluid bathes the ependymal cells in order to facilitate active transportation of few vital substances. Overall, there are four such vascular portions in the brain and each is composed of a sheet of cuboidal epithelial cells encircling the central capillaries and connective tissues. The ependymal layer of cells borders the ventricles along with the epithelial cells. Since these membranous tissues are adhesive in nature, the layer acts as a barrier to a large number of unessential molecules. The nerve complex undergoes folding to form finger-like processes and inserts the ventricles. The hair-like projections are instrumental for increasing the surface area of the plexus.
Choroid plexus Function
The modified ependymal cells of the vascular membrane produce 500 ml of cerebrospinal fluid per day. Interestingly, the spinal fluid is continuously recycled to filter out the metabolites, foreign particles and other toxic products. The nerve plexus acts as good blood- cerebrospinal fluid barrier by filtering the plasma from the fluid with the help of epithelial cells. An osmotic gradient is properly maintained by the vascular structure which has the ability to transport sodium, chloride and bicarbonate ions into the ventricles. It regulates the external environment of the brain by draining the excessive quantities of neurotransmitters present in the cerebrospinal fluid.
Choroid plexus Diseases
Cysts may develop in the nerve complex during the development of the fetus. The condition could lead to a genetic defect in the future. However, medical experts consider these lesions to be benign in young children. Imaging techniques can be used to diagnose these fluid-filled cysts as a part of prenatal screening. In rare instances, a malignant tumor may often occur in children below the age of 2 and cause choroid plexus carcinoma. Affected patients suffer from constant headaches, nausea and macrocephaly. In some cases, excessive growth of the epithelial cells of the vascular structure can give rise to a neoplasm or tumor. This slow-growing, intracranial lesion is normally called choroid plexus papilloma. Although the abnormal mass is benign in nature, it could increase the production of cerebrospinal fluid and lead to hydrocephalus.
Choroid plexus Pictures