Anatomy and Physiology of the Vagina

Anatomy and Physiology of the Vagina

I ummed and ahhed about the best way to approach this section, because the reality is that there is so much to convey about the wondrous anatomy and physiology of the genitourinary system, most of which is probably unfamiliar to most vagina owners. The detail-orientated me wanted explanations of every microbe, presentation and influence, which in itself is a textbook for another time.

So, while there is no way I can educate you on every little detail, I can give you some pointers to ensure you are caring and being cared for appropriately.


To really get to the bottom of the issue we need to get a few things straight. The most important bit of misinformation to correct is terminology. To describe this wondrous area there is more than the anatomical term vagina. 

In fact, there a range of fabulous terms to describe every small nook and cranny, fold and flap, nub and bump, opening and exit. But the most important thing to set straight is that the internal genitalia, i.e., the tube that starts at the cervix and ends, and the opening, is called the vagina, and external to that, is collectively called the vulva. You see, this is a sticking point for many advocating for female sexual health, because interchanging vulva and vagina is so far from correct, it is like calling a penis a testicle. Got it?

Every piece of anatomy has a role to play; secreting, lubricating, covering sensitive tissues, a receptacle for intercourse, a channel for menstruation and childbirth. At the very core of all these activities of inside meeting the outside, is a finely tuned immune system existing on and within the surface of the delicate tissues of the vagina (and the vulva) known as the vaginal epithelium. 

Like other mucous membranes such as the respiratory system and the digestive system; the vagina maintains its own immune vigilance and response with the help of microbes. Because, for a small tube (with amazing accommodating stretching potential) it sure can be challenged by external and internal factors. Known as the vaginal microbiome, the microbes of the vagina regulate a fine balance of acidity (3.8-4.5…which is pretty darn acidic), guard against disrupting incoming microbes and respond and create metabolites in rhythm with the hormonal fluctuations over a lifespan and menstrual cycle.

Before I discuss these microbes and their relationship to your hormones in some more detail, I wanted to bring your attention to the wonders of your vaginal pH, for those of you who don’t suffer from regular or recurrent infections.

The acidic pH of the vagina maintains and protects the vagina from infection and is able to rebound (with the help of the microbes) after any number of pH-challenging and disrupting activities, such as: Menstruation, Ejaculation, Douching, Saliva, Lubricants, Sex toys and inserted devices, Smoking (yes being a cigarette smoker can shift the environment).

But if infection is recurring, then these activities need to be looked at and modified so that the pH can regulate and recover (again with the help of beneficial microbes) And that doesn’t mean no sex. It means minimising some components that disrupt pH (usually by introducing barrier methods and using more natural and pH correct lubricants). In addition, other factors need to be considered:

Vaginal Epithelium

The tissues or vaginal epithelium (cells and surface) within the vagina are highly responsive to hormones and hormonal fluctuation.

There is proliferation of epithelial cells along with an increase in the number of cell layers in response to the menstrual cycle and oestrogen levels

As cellular density increases, there is an associated increase in glycogen levels. The glycogen acts as a fuel source for Lactobacilli bacteria within the vagina, which influences the ability of the vagina to resist infection

So, at different stages of a menstrual cycle you will have slightly different microbes inhabiting your vagina. This is important from a health perspective, as often people report that symptoms of infection or imbalance will always appear around a specific time of their cycle. And as far as clues to getting to the bottom of recurrent or repetitive genitourinary infections, hormonal fluctuations can be key.

TIP: If you are having recurrent symptoms, track where they occur in relation to your menstrual cycle.

What Microbes?

Generally (and there are exceptions) the hallmark of a healthy vaginal microbiome is a dominance of Lactobacilli spp. microbes. These bacteria work very hard to produce acids, like lactic acid and hydrogen peroxide, which maintain the environment. They are also responsible for producing a range of other natural chemicals which are antimicrobial, antiviral, antifungal, break down biofilms (the soupy mucus around microbes that prevent antibiotics from affecting them) and regulate the environment in health and disease.

Believe it or not, there is also a fungal microbiome which is less understood at this stage, but most probably maintains its own balance and has synergistic and antagonising relationships with other microbes like different fungi, viruses (yes, we have those in this area too) and bacteria. Although hormone-induced changes occur in the other tissues and organs of the female reproductive system, the vaginal epithelium is more sensitive, and its structure is an indicator of oestrogen levels, and subsequently, infection resistance.

Stage of Life Influences

In different stages of life, oestrogen status and associated vaginal epithelial health will differ. In childhood, microbes inhabit this area that are completely different to the microbes that start to appear just before adolescence (less oestrogen, more different types of bacteria, less thrush). 

In pregnancy, there are less microbial fluctuations (which can be good), but the higher oestrogen levels mean that fungal microbes like Candida may be more problematic. Or if there was a microbial imbalance or tendency leading into pregnancy, microbe-associated pregnancy complications may dominate. 

In menstruation, the oestrogen peaks of ovulation often harbour a Candida risk, as does the joint peak of oestrogen and progesterone in the mid-luteal phase. A few days before menstruation, as levels decline, infections like Bacterial Vaginosis (BV) become more problematic. They are also quite common after menstruation, as the pH of menstrual blood shifts the environment and allows bacterial species known as anerobic bacteria to proliferate and grow.  

Menopause and perimenopause can bring a new range of issues for the area. Fluctuating and erratic oestrogen in perimenopause may see an increased risk of oestrogen-loving Vulvovaginal Candidiasis occur. On the flip side, infections that are bacterial, like BV and the lesser known Aerobic Vaginitis (Strep, E.coli, Staph) can dominate when oestrogen levels have dropped. The decline in oestrogen also means that the tissues of the urinary tract and external genitalia can start to change and waste (atrophy), leading to an array of symptoms like urinary irritation, urinary tract infection, infective discharges, pain, dryness, and some pretty serious and life-impacting symptoms. It is more than a bit of dryness on intercourse. The genitourinary syndrome of menopause (GSM) can be relentless and devastating for some. The issue in this life stage is that oestrogen isn’t recoverable, so the transition of microbes and the subsequent symptoms can be severe and generally get worse, not better, without intervention (natural or pharmaceutical).

In all of these stages of life, barriers to accessing or receiving care exist. Younger children often can’t or won’t communicate their issues. People often self-diagnose any discharge as thrush (tip: the most common vaginal infection is BV) and easy access to over-the-counter thrush medications often means the correct treatment isn’t used and the issue recurs. Often people are ashamed or reluctant to speak about their genitourinary health, and smells like the classic fishy odour of BV are stigmatised; society shames people for a discharge that requires treatment. Interestingly, surveys of professionals also reveal a reluctance to ask directly about vulval and vaginal health.

TIP: Not all discharges are thrush

So, the thing you need to ask yourself is:

“If I don’t bring it up, who will”?

Recognising your ebb and flow: why understanding your rhythm and triggers is important

It is important to understand how the health of this area is impacted by internal and external influences so that you can recognise what and how any issues are related to your cycle or hormonal balance. Breaking cycles of recurrence often requires a true understanding of how symptoms are related, a pattern recognition that is specific for you. Without the details, the treatment of issues can only ever be symptomatic.

Plot the detail, make the marks on your calendar. Being aware of what constitutes a normal and healthy discharge will help you identify when it changes. Thinking about what has been happening in your life will help you make the connections that others cannot.  

You also need to be prepared to talk about it. If you can’t have the conversation about your own health, how can you expect to get help with it. Vulval and vaginal health is intrinsically linked in with our whole body. One system affects another. If you don’t discuss it, a whole part of your health history is ignored.

As a clinician, I find that many are relieved to be able to open up, to be asked things they have never been asked before, to be able to understand their body on a whole new level.

Worth the risk, don’t you think? 

By Moira Bradfield Strydom

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