Hellekant - Spermatogenesis Flashcards
Compared to oogenesis, what is a big difference with spermatogenesis?
Spermatogenesis occurs throughout life - both mitosis and meiosis occur through adult life
What is the ploidy, chromosome, DNA copy and chromatid numbers of spermatogonium?
2N, 46 chromosomes; 2C DNA, and 46 chromatids
What process is entered by spermatogonium?
Spermatocytogenesis (mitosis)
What is the ploidy of the primary spermatocyte?
Diploid - 2N
What is the number of chromosomes in a primary spermatocyte?
46 chromosomes
How many DNA copies does a primary spermatocyte have? Chromatids?
4 copies, 2x46 chromatids
What process does a primary spermatocyte enter?
Meoisis I
How may secondary spermatocytes are made from a primary spermatocyte?
Two
What is the ploidy of a secondary spermatocyte?
Haploid (N)
How many chromosomes does a secondary spermatocyte have?
23
How many copies of DNA does a secondary spermatocyte have?
2 copies
How many chromatids does a secondary spermatocyte have?
2x23 chromatids
What process does a secondary spermatocyte enter?
Meiosis II
How many spermatids are produced from the two spermatocytes?
Four
What is the ploidy of the spermatids?
Haploid
How many chromosomes does the spermatid have?
23 chromosomes
How many copies of DNA does a spermatid have?
One copy
How many chromatids does does a spermatid have?
23
In regards to the seminiferous tubules, where are Sertoli cells found? Germ cells? Leydig cells?
Sertoli and germ cells reside within the seminiferous tubules; Leydig cells reside outside the tubule
In regards to sertoli cells, where does spermatogenesis occur?
Between the sertoli cells
What is a spermatogenic wave?
Time it takes for the reappearance of the same stage within a given segment of the seminiferous tubule
How long is mitosis of spermatogonia?
16 days
How long is the first meiosis in spermatogenesis? Second meiosis?
24 days; second meiosis few hours
How long does spermiogenesis take?
24 days
How long is the approximate cycle of spermatogenesis?
64 days
In sperm production, what cells are most sensitive to drugs or environmental conditions?
Spermatocytes
What cells secrete inhibin? What is the action of inhibin?
Sertoli cell; inhibin has negative feedback on FSH
What cells phagocytize defective sperm?
Sertoli cells