Ovary
General
Embryology
Author: Mohiedean Ghofrani, M.D.
Last author update: 1 November 2011
Last staff update: 5 June 2023
Copyright: 2002-2023, PathologyOutlines.com, Inc.
PubMed Search: Embryology [title] ovary
Cite this page: Ghofrani M. Embryology. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarynontumorembryology.html. Accessed June 5th, 2023.
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
AFIP images
Undifferentiated gonad - 38 days ovulation
Ovulation - 48 days
Ovulation - 5 months
Negative stains
- Ovarian surface epithelium is negative for CA125, unlike other coelomic derivatives
