Development of the OVARY
develops from:
• Coelomic epithelium: forms follicular cells.
• Primordial germ cells: form oogonia.
• Intermediate mesoderm: forms connective tissue stroma.
• Indifferent stage: indifferent gonad is formed.
• Different stage:
– In 6th week, primordial germ cells migrate into genital ridge.
– Under influence of primordial germ cells, primitive sex cords form:
cortical sex cords Primitive sex cords degenerate & are replaced by stroma that
forms ovarian medulla.
– surface epithelium gives rise to secondary sex cords which penetrate into
cortex
– In 4th month, these cortical cords break up into isolated cell clusters
(primordial ovarian follicles) each of which surround the oogonium as follicular
cells
– Tunica albuginea is poorly developed & surface epithelium continues to
proliferate, unlike that of male, so epithelial cells are continuously formed
during fetal life.
– Active mitosis of oogonia occurs during fetal life producing thousands of
primordial follicles. No oogonia form postnatally.
develops from:
• Coelomic epithelium: forms follicular cells.
• Primordial germ cells: form oogonia.
• Intermediate mesoderm: forms connective tissue stroma.
• Indifferent stage: indifferent gonad is formed.
• Different stage:
– In 6th week, primordial germ cells migrate into genital ridge.
– Under influence of primordial germ cells, primitive sex cords form:
cortical sex cords Primitive sex cords degenerate & are replaced by stroma that
forms ovarian medulla.
– surface epithelium gives rise to secondary sex cords which penetrate into
cortex
– In 4th month, these cortical cords break up into isolated cell clusters
(primordial ovarian follicles) each of which surround the oogonium as follicular
cells
– Tunica albuginea is poorly developed & surface epithelium continues to
proliferate, unlike that of male, so epithelial cells are continuously formed
during fetal life.
– Active mitosis of oogonia occurs during fetal life producing thousands of
primordial follicles. No oogonia form postnatally.
