Choroid plexus

Source: Wikipedia, the free encyclopedia.
(Redirected from
Blood–cerebrospinal fluid barrier
)
Choroid plexus
lateral and third ventricles.
Details
Identifiers
Latinplexus choroideus
MeSHD002831
NeuroNames1377
TA98A14.1.09.279
A14.1.01.307
A14.1.01.306
A14.1.01.304
A14.1.05.715
TA25654, 5786, 5980
FMA61934
Anatomical terms of neuroanatomy]

The choroid plexus, or plica choroidea, is a

cilia on the ependymal cells move to circulate the cerebrospinal fluid.[4]

Structure

Location

subarachnoid space

There is a choroid plexus in each of the four

anterior horn. In the third ventricle, there is a small amount in the roof that is continuous with that in the body, via the interventricular foramina, the channels that connect the lateral ventricles with the third ventricle. A choroid plexus is in part of the roof of the fourth ventricle
.

Microanatomy

The choroid plexus consists of a layer of

tight junctions[8] between the cells on the side facing the ventricle (apical surface). These tight junctions prevent the majority of substances from crossing the cell layer into the cerebrospinal fluid (CSF); thus the choroid plexus acts as a blood–CSF barrier. The choroid plexus folds into many villi around each capillary, creating frond-like processes that project into the ventricles. The villi, along with a brush border of microvilli, greatly increase the surface area of the choroid plexus.[citation needed] CSF is formed as plasma is filtered from the blood through the epithelial cells. Choroid plexus epithelial cells actively transport sodium ions into the ventricles and water follows the resulting osmotic gradient.[9]

The choroid plexus consists of many capillaries, separated from the ventricles by choroid epithelial cells. Fluid filters through these cells from blood to become cerebrospinal fluid. There is also much active transport of substances into, and out of, the CSF as it is made.

Function

CSF circulation

The choroid plexus regulates the production and composition of

xenobiotics into and out of the brain.[10][11]
In this way the choroid plexus has a very important role in helping to maintain the delicate extracellular environment required by the brain to function optimally.

The choroid plexus is also a major source of transferrin secretion that plays a part in iron homeostasis in the brain.[12][13]

Blood–cerebrospinal fluid barrier

See also: Glymphatic system

The blood–cerebrospinal fluid barrier (BCSFB) is a fluid–brain barrier that is composed of a pair of membranes that separate blood from CSF at the capillary level and CSF from brain tissue.

epithelial cells and tight junctions that link them.[14] There is a CSF-brain barrier at the level of the pia mater, but only in the embryo.[15]

Similar to the blood–brain barrier, the blood–CSF barrier functions to prevent the passage of most blood-borne substances into the brain, while selectively permitting the passage of specific substances (such as nutrients) into the brain and facilitating the removal of brain metabolites and metabolic products into the blood.[14][16] Despite the similar function between the BBB and BCSFB, each facilitates the transport of different substances into the brain due to the distinctive structural characteristics of each of the two barrier systems.[14] For a number of substances, the BCSFB is the primary site of entry into brain tissue.[14]

The blood–cerebrospinal fluid barrier has also been shown to modulate the entry of leukocytes from the blood to the central nervous system. The choroid plexus cells secrete cytokines that recruit monocyte-derived macrophages, among other cells, to the brain. This cellular trafficking has implications both in normal brain homeostasis and in neuroinflammatory processes.[17]

Clinical significance

Choroid plexus cysts

Main article:
Choroid plexus cysts
See also: Triple test

During

choroid plexus cysts may form. These fluid-filled cysts can be detected by a detailed second trimester ultrasound. The finding is relatively common, with a prevalence of ~1%. Choroid plexus cysts are usually an isolated finding.[18] The cysts typically disappear later during pregnancy, and are usually harmless. They have no effect on infant and early childhood development.[19]

Choroid plexus cysts are associated with a 1% risk of fetal

Edwards syndrome (trisomy 18) cases will present with choroid plexus cysts, as well 1.4% of Down syndrome (trisomy 21) cases. ~75% of abnormal karyotypes associated with choroid plexus cysts are trisomy 18, while the remainder are trisomy 21.[18]

Other

There are three

graded types of choroid plexus tumor that mainly affect young children. These types of cancer
are rare.

Etymology

Choroid plexus translates from the Latin plexus chorioides,[21] which mirrors Ancient Greek χοριοειδές πλέγμα.[22] The word chorion was used by Galen to refer to the outer membrane enclosing the fetus. Both meanings of the word plexus are given as pleating, or braiding.[22] As often happens language changes and the use of both choroid or chorioid is both accepted. Nomina Anatomica (now Terminologia Anatomica) reflected this dual usage.

Additional images

  • Coronal section of inferior horn of lateral ventricle.
    Coronal section of inferior horn of lateral ventricle.
  • Choroid plexus histology 40x
    Choroid plexus histology 40x
  • Choroid plexus
    Choroid plexus
  • Choroid plexus
    Choroid plexus
  • Choroid plexus
    Choroid plexus

See also

This article uses anatomical terminology.

References

Public domain This article incorporates text in the public domain from page 798 of  page 841 of  page 816 of the 20th edition of Gray's Anatomy (1918)

  1. ISBN 978-0-7817-9069-7
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  14. ^ a b c d e Laterra J, Keep R, Betz LA, et al. (1999). "Blood–cerebrospinal fluid barrier". Basic Neurochemistry: Molecular, Cellular and Medical Aspects (6th ed.). Philadelphia: Lippincott-Raven.
  15. PMID 26998242
    . The embryonic CSF-brain barrier, shown in Figure 1(f). In the ventricular zone is a temporary barrier between the CSF and brain parenchyma. In early brain development, strap junctions are present between adjacent neuroepithelial cells; these form a physical barrier restricting the movement of larger molecules, such as proteins, but not smaller molecules. At later stages of development and in the adult brain, these strap junctions are no longer present when this interface becomes ependyma.
  16. S2CID 22154007
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  17. PMID 24357543
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  18. ^
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  21. ^ Suzuki, S., Katsumata, T., Ura, R. Fujita, T., Niizima, M. & Suzuki, H. (1936). Über die Nomina Anatomica Nova. Folia Anatomica Japonica, 14, 507-536.
  22. ^ a b Liddell HG, Scott R (1940). A Greek-English Lexicon. Oxford: Clarendon Press.

Sources

External links

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