Basics Set: Female Reproduction, Part 1

Feb 17 2010 Published by under Basic Science Posts

Sci was handed a paper a few days ago, on the concept of evolutionary psychology (or physiology, possibly) and mate choice due to things like birth control. She thought she'd blog it. And then she realized that, to blog it successfully, she was going to have to do some MAJOR background. And then she had an idea!

It's time for another series, y'all.
And so, without further ado: the female reproduction series.
This series is going to be broken up into a couple of section. Today's will be the basic anatomy. Then we'll be covering the female cycle in all its glory and all its hormones, and then on to the basics of fertilization and possibly pregnancy. It's gonna be a good time. Except for the fact that a lot of the hormones don't have very good names. But that's ok.
Let's do it ladies. (Pics probably NSFW, even though it's straight up anatomy, some people probably shouldn't be staring at vaginas during work hours.)

(This woman can DANCE. And you gotta love a woman with some good curves. /Beyonce worship)

First up: The ANATOMY

One of the first things you'll notice in that picture above is that the ovaries and uterus are a LOT lower than most people think they are. Ask a woman to put a hand on her uterus and most women will head for an area just below the belly button. Nope, lower. LOWER. Actual position is probably going to be just above the pubic hair line.
And now we get to the major anatomy. First you can see the globs on either side, the ovaries. This is where the real action is going to be during the monthly cycle. When eggs are released from the ovaries, they travel into the tubes just above them, the fallopian tubes. Usually an egg gets all the way down to the uterus before fertilizaton, but if it doesn't, and is fertilized and implants in the fallopian tubes, this is very bad news for everyone (though sometimes the egg can even implant in the ovary or in the abdomen, and that's REALLY bad news for everyone). So we all are rooting for the egg to get through the fallopian tubes to the uterus.
The uterus is where the baby action happens. You can see in the picture above that the uterus has two major layers to it (well, actually it has three, there is a very far outer layer called the perimetrium, that separates the uterus from the rest of the abdominal environment). The thick layers is the myometrium, which is a muscle layer made of smooth muscle, which also support a lot of blood flow. This is the layer that will stretch during pregnancy, and the smooth muscle will provide the contractions that occur during labor.
The thinner inner layer is the endometrium, a spongy glandular tissue layer which gets thickened and blood filled each month, and is shed during each menstrual cycle. During pregnancy, this endometrium will provide the implantation area for the fetus, and form the maternal half of the placenta.
Further down we have the cervix. This is a narrowing of the uterus, where it joins the top part of the vagina. Through a speculum it looks like this:

See that slit in the middle? That's the opening up toward the uterus. Yes, a baby's gotta get through that. This is why the dilation of the cervix during birth is so vitally important. Like getting a pot roast through a cheerio.
And further down we get to the vagina.
An aside on vaginal anatomy:

(Yes, yes, it has hair. Shocking, I'm sure. C'mon, we're all mammals, here.)
All right, so we'll start at the top. You can see here that the clitoris is very small, and covered in most women by the clitoral hood (which is sometimes removed during "female circumcision", which is an ethical and humanitarian issue that Sci is not going to cover today). On the sides you can see the fleshy labia major ("major lips"), and inside those, the labia minora ("Minor lips"). Within these two labia are the urethral open through which a woman urinates, and her vaginal opening, which is further back. The anus is the furthest back and is not surrounded by the vaginal labia.

A side rant
: Sci recently heard that there is a plastic surgery that can be done to reduce the size of the vaginal lips and make them look more like pr0n starz. Apparently there are also surgeries you can have to make your vaginal opening smaller, and thus tighter. She cannot tell you how incredibly angry these surgeries make her. Honey, if your man insists that you need smaller vaginal lips to be attractive, or a tighter vaginal opening to be sexy, or you think you need that to be attractive to men: YOU ARE WITH THE WRONG MEN. Ain't nothing about "tightness" that Kegels can't fix, unless you require repair from significant tearing due to birth or other trauma. That is all.
Ok, so now we're through the major anatomy. And next time (with a break for weird science) it's on to the hormones and the glory of the menstrual cycle.

14 responses so far

  • josef says:

    Regarding size-0 women. "If you want a boy, get a boy".

  • nikipedia says:

    The love I have for both Beyonce and this series are making me doubt my heterosexuality. Thank you so much for writing this. I really loved your oxytocin series and both that and this one are somewhat germane to my work, so I am really looking forward to the rest.

  • Joneziziz says:

    Honey, if your man insists that you need smaller vaginal lips to be attractive, or a tighter vaginal opening to be sexy... YOU ARE WITH THE WRONG MEN.


    [if] you think you need that to be attractive to men: YOU ARE WITH THE WRONG MEN.


  • Jason says:

    This is the greatest sentence in the history of science writing: "Like getting a pot roast through a cheerio."

  • Shira says:

    Great post, but I have to correct your description of the clitoris as "very small." It's a common misconception that the clitoris consists only of the small external portion visible on the drawing above. The clitoris extends deeply internally, and becomes erect during arousal. Here is a great youtube video showing the internal structure of the clitoris.

  • anna says:

    An aside as regards the labiaplasty/reduction you mentioned:
    I do agree it is generally unnecessary for "visuals", but I have had friends who rejoiced when this became common enough.
    Why? They were the owners of some (usually single-sided) long labia that were constantly getting squished & pinched & sat upon, and generally uncomfortable. For them, the chance to have this physical impediment corrected meant a life of pain-free bicycle riding and pants-wearing.

  • megan says:

    Yes, women's clitorises can come in varying sizes to the extreme of a miniature penis in as much as some men can have penises so small/thin as to be practically huge clitori when non-erect.
    In further agreement with the above poster, a woman's clitoris internally is like the sponginess blood tissue for males but has been left inside and along the walls of the vagina.
    Basically you can see how nature and evolution has just used the SAME physical structures and organs but for different purposes in either sex. Ovaries=Testes, clitoris=penis, Cervix and uterus =(imho) prostate muscle structure, both sexes have sexually responsive nipples. That's why stimulation during copulation really isn't too different for either sex as the tactile nerves are the same and in th nearly same proportions and sensitivities.

  • Matt says:

    I appreciate the sentiment in going against the "every woman must be a size zero" trend. But it's not cool to go in the other direction, either, and insinuate that women who are naturally petite are unfeminine and ugly.

  • DuWayne says:

    Sci -
    While I can totally appreciate the notion that "all women must be 0 size, it should be noted that there are a lot of women who are that size because no matter what they eat or how, they metabolize it quickly. Saying it is nice to see "WOMEN" on stage, implies that someone who is extremely petite is not a woman. Honestly, I don't see a hell of a lot of difference between that and implying that gays aren't real men. I respect you a great deal, but that comment was more than a little disappointing.
    Josef -
    Regarding size-0 women. "If you want a boy, get a boy".
    Fuck you asshole. Seriously, fuck you. I am with my partner because she is fucking brilliant, because I can talk about a lot of intellectually stimulating topics and her eyes don't glaze over. And I am with my partner because she most certainly fuckingwell is a woman. That she happens to be very skinny, is irrelevant and completely outside of her control.

  • Scicurious says:

    DuWayne and Matt: Sigh. I can edit it out. One of those things that I meant to sound empowering to ladies with curves, and came off offensive instead. Let's NOT make this comment thread about size, because that is not, in fact what this post is about, and I didn't mean to offend anyone. I'll take it out.
    Josef: yeah, you sound like a jerk, actually.

  • IrishMom says:

    "Like getting a pot roast through a cheerio."
    Bwaaahahahahahaha. Aaaaahahahahahahahahaha. *snort*
    Okay...I caught my breath.
    That is my new favorite sentence.

  • DuWayne says:

    When youngest was born, we went straight into c-section mode, so holding her hand wasn't bad - though it took a lot of pain meds to get her down. With eldest OTOH, momma was in labor for more than 36 hours before we finally convinced her fucking hippie doctor to bring in the residents for a c-section.
    I thought she was going to break my hand, when hippie doctor was pressing her to push (tearing a lot of shit up inside).
    My worse pain ever, was much like pushing a pot roast through a cheerio. I passed three stones total, the largest being slightly larger than regular marble.
    I would note that eldest's birth was really fascinating, because they actually pulld the uterus part way out, then made the incision into that and pulled eldest out. The nurse unfortunately, left a lot to be desired on several levels - first trying desperately to discourage me from watching - even after I explained that I had actually seen the bone of my middle finger, left hand. Then she asked a lot of invasive questions about whether momma had been drinking during pregnancy - refusing to back down after I made it clear that she hadn't. Never occurred to her that eldest was pretty mellow and disinclined to cry, because they had to pump her full of painkillers, some of which filtered to him...But I digress. The uterus is rather fascinating and removing the baby from that is even more fascinating.
    Honestly, it reminded me of one fo the Alien movies - though eldest did not fight/bite his way out, skitter across the floor and try to kill people...

  • Jim says:

    lol, Sci does reproduction 😉
    The first thing that strikes me when I see the classic (schematic) image of the female anatomy is how it conveys that most women are walking around with half a pint of air or liquid in their uterus.
    Would it be so hard to draw as the uterus as a shape akin to "Y" and still be identifiable? Trivia point, you'd be lucky to get more than half a pint of uteral fluid from a conference room full of healthy, all be it non-gestating, women 😉

  • I have to agree with Jim. The anatomical illustrations are trying to convey that "this here is the lumen, where the baby goes"...but the representation is not accurate. The lumen is much much smaller and the sides of it are quite likely in contact with one another much of the time. But if we were to represent it as such, I think a lot of people could be confused as the the layers of tissue, etc.

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