PHY3181 Lecture Notes - Antral Follicle, Oogenesis, Theca Interna
4 Jun 2018
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Week 5. Ovarian Physiology and Female Reproductive
Endocrinology
OVARIAN PHYSIOLOGY
• The female reproductive tract
• Formation of the ovary
o GREL cells in the primordial ovary gives rise to the granulosa cells and surface epithelium
o Stromal cells play an important role as the surround and break up original Oogonia into
separate cells/structures
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• Oogenesis – development in the foetal ovary
o Production of female germ cells
o Primordial germ cells migrate to the coelomic epithelium of the gonadal ridges
o After embryonic sexual differentiation, primordial germ cells proliferate and become
Oogonia
o By week 20 of pregnancy, ~7 million Oogonia are present
o Going from diploid to haploid (can take up to 50 years)
• Oocyte development:
o Most follicles are primordial, some are early primary as well
o Not going to have any more oocytes – ells dot diide fro this poit o
• The ovary at birth:
o Most follicles remain in the resting stage
o This pool of follicles constitutes the ovarian reserve including:
Primordial oocyte:
▪ Surrounded by flattened granulosa cells (precursor)
Transitory follicle:
▪ Oocyte surrounded by a mix of flattened and cuboidal granulosa cells
▪ Moving between primordial and primary stages
Small primary follicle:
▪ Oocyte surrounded by a single layer of cuboidal granulosa cells
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• Ovarian reserve:
• What are follicles:
o Basic unit of female reproduction
o Roughly spherical cellular structure
o Comprises:
Oocyte (egg)
Granulosa cells
Theca cells (differentiated from stromal cells, flattened cells outside granulosa)
o Develop from primordial follicle to ovulation by a number of different stages
o Many different stages of development can be seen in an ovary at one time
-> hundreds/thousands of follicles are recruited
-> takes more than primary follicles to develop into secondary follicles
-> takes 3 cycles until we get a dominant follicle (get different cohorts – waves)
• Time course of follicle development:
o Ovulation occurs once every 28 days where the dominant follicle ovulates
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Primordial oocyte: surrounded by flattened granulosa cells (precursor) Transitory follicle: oocyte surrounded by a mix of flattened and cuboidal granulosa cells, moving between primordial and primary stages. Small primary follicle: oocyte surrounded by a single layer of cuboidal granulosa cells, ovarian reserve, what are follicles, basic unit of female reproduction, roughly spherical cellular structure, comprises: Theca cells (differentiated from stromal cells, flattened cells outside granulosa: develop from primordial follicle to ovulation by a number of different stages, many different stages of development can be seen in an ovary at one time. > takes more than primary follicles to develop into secondary follicles. > takes 3 cycles until we get a dominant follicle (get different cohorts waves: time course of follicle development, ovulation occurs once every 28 days where the dominant follicle ovulates, different types of follicles: Primary follicle: the most basic follicle, can only observe oocyte, surrounded by flattened layer of cells, small primary follicle:
