Ovary Development

From Embryology

Introduction

File:Infant ovary

The female gonad is the ovary and is closely associated with female internal genital (reproductive) tract development. In humans, these laterally paired organs lie within the peritoneal cavity.

Initial gonad development in females and males is virtually identical with germ cells migrating into an indifferent gonad. In females with XX, the ovary then begins to develop and the subsequent structure and timecourse of germ cell then differs between males and females. In the ovary oocytes proliferate prior to birth and arrest in meiosis 1.

Links: X Chromosome | System - Female | Week 1 - Oogenesis


Oogenesis

Human ovary oocyte number

This graph shows the changes in human germ cell numbers in the ovary with age.

Total numbers peak at about 7 million (occuring in early fetal development) and then decreasing by apopotic cell death.

At puberty there remain only about 400,000 and only about 10% of these will be released through reproductive life.

Infant Ovary

Histology of the female infant ovary

This image shows a region (see inset) of the infant ovary cortex.

There are a large number of developing oocytes which will eventually form a dense primordial germ layer at the ovary periphery.

Later stages of follicle development are completely absent and will begin to only appear just prior to puberty.