|WikiProject Molecular and Cellular Biology||(Rated B-class, High-importance)|
Heat and spermatogenesis
Someone should research and write the information concerning the temperature at which spermatogenesis will actually occur. They should also comment on how the scrotum helps to regulate this temperature as needed to halt or start spermatogenesis. This information would also be useful for those of use that get really saggy balls after sex and have trouble sleeping because of it. You know then every one would know that a cold pack on the taint will tighten those suckers back up. I am completely serious about this because I was just perusing wikipedia for the same information after this exact situation. MCP 05:24, 29 December 2005 (UTC)
- The textbook answer is that spermatogenesis occurs at 2-4 degrees celsius below body temperature. Occupational exposure to heat (e.g extended sitting, bakery workers) has been associated with male infertility.
- The anatomy of the scrotum (in humans) keeps its contents cooler than the rest of the body (low fat content in the subcutaneous tissue and a counter-current heat exchanger in the cord). The purpose of such regulation is to keep spermatogenesis going. i.e it is not regulated in a stop/start fashion. I don't know if that happens in any animal species.
- When I get some time, I'll add this section to the article. I don't have the relevant references handy right now.Tony Makhlouf
- Thank you, that kind of info was very useful, but there is one question I have. If spermatogenesis is continuous without halting, what keeps your nutz from exploding. Seriously? Maybe you should add the bodies solution for that too, so there are few questions concerning that. MCP 08:13, 30 December 2005 (UTC)
- Remember, sperm only makes up a small amount of ejaculate, most of it is semen. I suppose the sperm is just reabsorbed... (see phagocytosis). Also, apparently laptops are *really* bad for this process, and shouldn't ever be kept on the lap. apparently.
- My question is - why demand lower temperatures? I have heard a lot that testicles are external due to spermatogenesis requiring lower temperatures, but why? Whats so special about it that it bucks the trend of all the other body processes? I thought 37-40 °C is as good as it gets for organic reactions within mammals? I feel as a male who's been kicked in the nuts once or twice it is owed to us to know why they're there? - Jak (talk) 02:47, 9 July 2006 (UTC)
We were always taught in anatomy that the testicles hang lower to show sexual maturity, with it having nothing to do with optimum temperature. Can someone find a referance for this? — Preceding unsigned comment added by 22.214.171.124 (talk) 16:37, 3 May 2012 (UTC)
According to "endocrinology, an integrated approach" : Sperm can be stored up to 5 weeks in the tail of the epididymis and vas deferens before they are released at ejaculation. In the absence of ejaculation sperm dribble into the urethra and are washed away in the urine. In men who have undergone a vasectomy (ligation of the vas deferens) sperm build up behind the ligation and are either removed by phagocytosis in the epididymis or leak through the epididymal wall. 5/06/06
- Do you have the full source info for this statement? Ya know, so others can read the source text? - Jak (talk) 02:34, 9 July 2006 (UTC)
The medieval theory of spermatogenesis was quite different from this. They believed that the sperm was actually male's "purest form" of blood, and that when ejaculation occured in the vagina, this sperm mixed with the cooler female blood, which created some sort of "bond" between the two. It was one of the reasons to forbid premarital sex, because the partners would then be linked somehow and a further marriage would be incestious. I don't know a lot about the subject, but i do remember reading it one book, i'll try to find that source. Should this be included in this article, since it is so different, or to another page? --MateoP 16:38, 2 February 2006 (UTC)
- A very fine detail of the history of medicine. The science should be established before the history. Maybe later - Jak (talk) 02:47, 9 July 2006 (UTC)
Another Question: I have heard things like "50 drops of blood being used for the creation of one drop of Semen"!! Seriously. Can someone tell me whether there is any role of blood in Spermatogenesis? Why is that we feel pale and exhausted after sex?? I have been doing a serious peruse of wikipedia for this!!
- If this is true, it will be that one drop of semen is the filtrate of 50 drops of blood. The other 49 drops of blood will continue to flow around the body. You feel exhausted because of all the exercise and/or overheating - Jak (talk) 02:47, 9 July 2006 (UTC)
'pre-testicular' and 'post-testicular'?
I've come across the above terms in the context of male infertility (including the Pedia articles on it) but can't find decent definitions anywhere. Could someone please put some in if possible? Thanks! --Tyranny Sue (talk) 01:18, 15 February 2010 (UTC)
Ok, I dont mean to be too picky, but im pretty sure the chromosmal orientation in primary spermatocytes and secondary spermatocytes is incorrect as discussed in this topic. This is how I understand it, and I have some literature that also infers what I am saying.
Primary Spermatocytes (4N)
Secondary Spermatocytes (2N)
Spermatid & beyond (N)
This may look crazy at first but it makes way more sense. How can you go through meiosis 2 without halving the chromosome count?? This always perplexed me until i looked into it furhter and found literature on the subject. Here it is:
1)Kimura, Y. (1995). Development of Normal Mice from Oocytes Injected with Secondary Spermatocyte Nuclei (in: BIOLOGY OF REPRODUCTION 53, 855-862)
2)Ogura, A. (1998). Development of Normal Mice from Metaphase I Oocytes Fertilized with Primary Spermatocytes (in: Proceedings of the National Academy of Sciences, Vol. 95, No. 10 pp. 5611-5615)(first paragraph of abstract)
3)Mays-Hoopes, L.L. (1995). Preparation of Spermatogonia, Spermatocytes, and Round Spermatids for Analysis of Gene Expression Using Fluorescence-Activated Cell Sorting. (in: BIOLOGY OF REPRODUCTION 53, 1003-1011)
4)This website lays it out pretty clear http://www.expertreviews.org/01002320h.htm
Actually, "N" refers to ploidy and "C" to DNA copy number, so spermatocytes are NEVER tetraploid (any more than any mitotically dividing cell is tetraploid). The correct nomenclature to use for a mitotically dividing cell is 2N:2C (Go), 2N:4C (DNA repl), 2N:2C (G1-G2 etc). For meiosis it is as follows. 2N:2C (Go), 2N:4C (DNA repl prior to MI ), 1N:2C (after MI), 1N:1C (after MII). All gametes are haploid after MI because both post-recombinationally modified chromatids of the replicated chromosomes segregate to the daughter cells, making them numerically haploid (1N). They still have two DNA copies though (2C) at this stage.
- The previous commentor is correct, and I have adjusted the table in the article to reflect this. I have used the copy number prior to replication/division for all cells (G1 for primary spermatocytes) to be consistent, and have indicated that the chromosome numbers refer to humans only, of course! Now the table is uglier than it was, but at least the N is fixed, and in the ploidy column where it belongs. Perhaps it would be better to put ploidy/DNA copy number in one column, and human chromosome/chromatid counts in another? Grothmag (talk) 21:09, 22 December 2010 (UTC)