Talk:2010 BGD Practical 3 - Gametogenesis: Difference between revisions
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==Spermatazoa Statistics== | |||
The following data is based normal human male values for reproductive ages between 20 to 50 years: | |||
* 45 to 207 million spermatozoa produced per day within the two testes | |||
* 2,000 spermatozoa approx per second each day | |||
* Compare this to adult human red blood cell production of about 250,000 million RBCs per day | |||
* 182 million spermatozoa stored (epididymal reserves) up to per epididymis | |||
* 440 million spermatozoa extragonadal stored | |||
* 225 million extragonadal spermatozoa in the ductuli deferentia and caudae epididymides per ejaculation | |||
* 23 million spermatozoa approx (all animals) per gram testicular parenchyma per day | |||
(Data: Amann RP, Howards SS., 1980 and Gordon-Smith EC., 2007) | |||
'''Female Oogenesis''' | '''Female Oogenesis''' |
Revision as of 00:04, 10 May 2010
Original page - http://embryology.med.unsw.edu.au/Medicine/BGDlabfertilization2.htm
Spermatazoa Statistics
The following data is based normal human male values for reproductive ages between 20 to 50 years:
- 45 to 207 million spermatozoa produced per day within the two testes
- 2,000 spermatozoa approx per second each day
- Compare this to adult human red blood cell production of about 250,000 million RBCs per day
- 182 million spermatozoa stored (epididymal reserves) up to per epididymis
- 440 million spermatozoa extragonadal stored
- 225 million extragonadal spermatozoa in the ductuli deferentia and caudae epididymides per ejaculation
- 23 million spermatozoa approx (all animals) per gram testicular parenchyma per day
(Data: Amann RP, Howards SS., 1980 and Gordon-Smith EC., 2007)
Female Oogenesis
Meiosis initiated once in a finite population of cells
1 gamete produced / meiosis
Completion of meiosis delayed for months or years
Meiosis arrested at 1st meiotic prophase and reinitiated in a smaller population of cells
Differentiation of gamete occurs while diploid (in first meiotic prophase)
All chromosomes exhibit equivalent transcription and recombination during meiotic prophase
Male Spermatogenesis
Meiosis initiated continuously in a mitotically dividing stem cell population
4 gametes produced / meiosis
Meiosis completed in days or weeks
Meiosis and differentiation proceed continuously without cell cycle arrest
Differentiation of gamete occurs while haploid (after meiosis ends)
Sex chromosomes excluded from recombination and transcription during first meiotic prophase
References
NCBI Bookshelf - Endocrinology: An Integrated Approach. Nussey, S.S. and Whitehead, S.A. Oxford, UK: BIOS Scientific Publishers, Ltd; 2001. The ovary - folliculogenesis and oogenesis | Spermatogenesis
Mitosis and Meiosis: MBoC Fig 20-6
Oogenesis: MBoC ch20f16.gif
Spermatogenesis: Dev Biol Ch19f18.jpg
Seminiferous Tubule: Dev Biol ch19f17.jpg