Germ Cell Development Flashcards
What are the specification and commitment steps in germ cell development?
Specification: blimp1 expression
Commitment: Stella
When do specification and commitment occur?
5.5-6.5 days
How do germ cells actively migrate to the gonads?
Move through the midline and the out to the gonads.
What are the four steps of germ cell development?
Specification, commitment, migration, colonisation.
When does extensive proliferation of germ cells occur?
During migration.
What two hormones drive the development of the male reproductive system?
Anti-Mullerian hormone and DHT
What is Swyer syndrome?
XY chromosomes with not SRY gene.
What is the phenotype of Swyer syndrome?
Externally female, streak ovaries, not secondary sex characteristic, no germ cells, can support gestation.
What does colonisation by the germ cells occur?
Weeks 6-8
When do cells begin to migrate in humans?
Week 4
When does meiosis stop at prophase I in females?
Week 12
What is the cause of carcinoma in situ?
Termination of germ cell differentiation and transformation.
What is the potency of seminoma cells?
Pluripotent
What is the function of Sertoli cells?
SRY gene
Anti-Mullarian hormone
Regulation of spermatogenesis
Blood-testicular barrier
What is the syncytium?
Connections between cytoplasms of germ cells-spermatids to ensure all sperm are identical.
What is the function of Leydig cells?
Produce testosterone
Located between the seminiferous tubules.
What is the primordial follicle?
Oocyte surrounded by cells of the ovary before birth
What is the oocyte like at birth?
Completely enclosed in follicular
What cells inhibit meiosis in oocytes?
Granulosa cells
When does meiosis first resume?
12 hours before ovulation
What happens once the dominant follicle is established?
It produces inhibin to signal to the pituitary to stop producing FSH so that other follicles die.
What are atretic follicles?
Those that die
What are the supporting cells of oocytes and sperm?
Granulosa and Sertoli.
What factors does the oocyte secrete to promote follicular cell growth?
BMP15 and GDF9
List the functions of follicular cells.
Secrete factors for meiotic arrest
Low-level androgen production
Respond to LH
Produce aromatase enzyme to convert androgen to oestrogen
List the function of Theca cels.
Angiogenic factor for blood supply to follicle
LH secretion
Oestrogen production
