 Hi everybody, Dr. O here. This is where we're going to talk about the vagina. So the vagina is a muscular canal that also has the ability to expand and it has two primary purposes. It is the entrance to the reproductive tract and it's obviously used in copulation, sexual intercourse, but it also serves as the exit from the uterus as a baby is delivered and also menstruation. As far as the anatomy of the vagina, you'll see this in other images in later videos as well. We have the fornic. So the fornic is going to be the superior most portion of the vagina that comes into contact there with the cervix and where the cervix is not part of the vagina. The cervix is the part of the uterus that extends into the vagina. So again, let me show you a picture here that shows how much the vagina can expand. So here we see dilation and birth. Obviously the vaginal canal is able to expand large enough to handle a baby, 9, 10 pounds potentially sometimes. That's going to be its primary function during labor and delivery of course. And then we have just as far as some other structures. I mentioned the Bartholens glands in the last videos, they're going to be the ones or they're called the greater vestibular glands. They're going to be the ones that lubricate the vagina during sexual intercourse. Last thing I want to talk about here, so there's not much to say about the vagina, just this muscular tube that also can expand. That's very, very important. But something that isn't talked about enough is the vagina has a vaginal microbiome. It has a normal, what should be a normal population of microbes living in it, combination of bacteria, yeast, viruses and everything else. But what makes the vaginal microbiome so unique is usually when we talk about the microbiome and we look at what constitutes a healthy microbiome. We talk about diversity. Having more species interacting with each other is the key to diversity in most microbiomes. But the only microbiome, that's not true, at least that I know of so far is the vaginal microbiome. You do not want a diverse microbiome. 70% or more of the microbes in the vaginal microbiome should be lactic acid producing bacteria in the family lactobacillus. So your lactobacillus, acidophilus, befitum, those kind of things. You want there to be a lot of lactic acid in the vagina. That's because the low pH of the vagina, so a healthy vagina where there's plenty of lactic acid from these fermenting bacteria would have a pH below four and a half. That's actually what inhibits the growth of pathogenic bacteria. So really the vagina is, if you have a healthy vaginal microbiome, the vagina is a self-cleaning organ. It doesn't need to be cleaned as far as pathogens are concerned because keeping that low pH inhibits the growth of pathogens, just like turning cabbage into sauerkraut. That low pH inhibits the growth of pathogenic bacteria. So this is the exception to the rule where you want a diverse microbiome. The vaginal microbiome should be dominated by these lactic acid fermenting organisms or lactic acid producers. So much so that one of the things you can do that really disrupts this microbiome is douching. If you're constantly cleansing the vaginal microbiome away by douching, that can cause problems. So much so that the American College of Obstetricians and Gynecologists says that you should not douch and you should not over clean the vagina because you want to keep that healthy microbiome intact. So that's pretty interesting, more of a top for microbiology, but still worth talking about now. So a diverse microbiome in the vagina, full of all sorts of different kinds of organisms, that actually increases your risk for bacterial vaginosis and those kind of things. Okay, so that's the vagina. We'll keep moving through the female proctor tract. I hope this helps. Have a wonderful day. Be blessed.