Ovary - nontumor
General
Embryology

Author: Mohiedean Ghofrani, M.D. (see Authors page)

Revised: 13 September 2017, last major update November 2011

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Embryology [title] ovary

Cite this page: Ghofrani, M. Embryology. PathologyOutlines.com website. http://pathologyoutlines.com/topic/ovarynontumorembryology.html. Accessed December 15th, 2017.
Definition / general
  • Ovary is composed of four main components, each with different embryologic origins, all of which eventually come together in the developed ovary: surface epithelium, stroma, germ cells and sex cords
  • Embryonic coelomic cavity is initially lined by primitive mesothelium (modified coelomic epithelium), which arises from the underlying mesoderm

    At approximately 5 weeks gestation, the gonadal ridge develops as a coelomic thickening and mesenchymal growth high in the abdominal cavity near where the kidneys develop:
    • Coelomic epithelium forms the ovarian surface epithelium
    • Subcoelomic mesoderm forms the ovarian stroma
    • Primordial germ cells migrate from the yolk sac endoderm to the developing ovary
    • Invaginations of coelomic epithelium in the superficial ovarian cortex form the sex cords (pregranulosa cells)

  • During weeks 12 - 20, the vascular network develops from the hilus towards the cortex and pregranulosa cells encircle germ cells to form primordial follicles, which in turn are encircled by stroma derived theca cells
  • Germ cells differentiate into oogonia, which differentiate into primary oocytes and arrest in this stage until puberty
  • Each ovary descends into the pelvis along the gubernaculum (attached inferiorly to the inguinal region); the gubernaculum becomes part of the uterine wall at entry of the fallopian tube and persists in adults as ovarian and round ligaments
  • Invaginations of the coelomic epithelium at the site of the gonadal ridge also give rise to two types of genital ducts: the mesonephric (Wolffian) ducts and the paramesonephric (Müllerian) ducts
  • Müllerian ducts eventually give rise to the fallopian tubes and fuse to form the uterus
  • Wolffian (mesonephric) duct remnants may be seen in the vicinity of the Müllerian system later in life
  • Gonadal development is influenced by both male and female promoting signals (Mol Endocrinol 2008;22:1)
  • Wikipedia: Gonadal Ridge, Embryology: Human Embryology
Microscopic (histologic) images

Images hosted on PathOut server:

Undifferentiated gonad - 38 days ovulation

Ovulation - 48 days

Ovulation - 5 months

Negative stains
  • Ovarian surface epithelium is negative for CA125, unlike other coelomic derivatives