Anatomy

Chorion

The outermost extra-embryonic membrane surrounding the developing embryo. In REPTILES and BIRDS, it adheres to the shell and allows exchange of gases between the egg and its environment. In MAMMALS, the chorion evolves into the fetal contribution of the PLACENTA.

National Library of MedicineMedical Subject Headings2026

Structured Summary

Abstract

The outermost extra-embryonic membrane surrounding the developing embryo. In REPTILES and BIRDS, it adheres to the shell and allows exchange of gases between the egg and its environment. In MAMMALS, the chorion evolves into the fetal contribution of the PLACENTA.

MeSH Record

Classification

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See Also

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Synonyms

1 entry terms
  • Chorions

MeSH Record

Aspects Covered

24 allowable subheadings

Indexed with the subheadings abnormalities, anatomy & histology, blood supply, chemistry, cytology, diagnostic imaging, drug effects, embryology, enzymology, growth & development, immunology, injuries, innervation, metabolism, microbiology, parasitology, pathology, physiology, physiopathology, radiation effects, surgery, transplantation, ultrastructure, virology.

MeSH Record

History Note

78(75); was see under FETAL MEMBRANES 1963-77

MeSH Record

Previous Indexing

  • Fetal Membranes (1966-1974)

MeSH Hierarchy

Tree Numbers

  1. A10w.615w.284w.473w
  2. A16.254.750w.473w

MeSH Record

NLM Classification

WQ 210

AMA Style

References

  1. National Library of Medicine. Chorion. Medical Subject Headings (MeSH). 2026. Unique ID D002823. http://id.nlm.nih.gov/mesh/2026/D002823
  2. Chorion. In: Wikipedia. https://en.wikipedia.org/wiki/Chorion_(egg)
  3. Chorion. In: Wikidata. https://www.wikidata.org/wiki/Q5105068