Female Anatomy Review Part II: The Internal Workings
The second part of our series on female anatomy involves the internal female organs. This is just a very general discussion on how they work independently and with each other and what happens when they’re not working properly. Please speak to your Oakland Macomb provider about specific questions you have regarding your anatomy or any changes or concerns you have about your health.
Cervix– deeper inside the body from the vagina you’ll find the cervix, which, though unique in cells and structure, is basically the first 2-3 cm of the uterus. It is basically an adaptable channel with a small opening (the external os) into the vagina and another (internal os) into the uterus. It is the access for sperm into the body, and for menstrual blood (from the shedding of the uterine lining) out of the body during your monthly menstruation. The tiny hole in the cervix widens (dilates) a small amount during menses and a large amount (ultimately 10 cm) during child birth, and the entire cervix relaxes and thins out to accommodate the baby. Then afterwards, it shrinks back to its original size and shape. The surface and inside lining of the cervix is what your provider is sampling during a Pap smear, to identify any early cellular changes that might lead to cervical cancer. This is also where Human papillomavirus can cause genital warts or cervical cancer. This is why we test for that virus and vaccinate against it for men and women now, as it is passed on from sexual contact and is extremely common (see previous post). The cervix is monitored closely during pregnancy to make sure it is staying tightly closed and intact until the appropriate time.
Uterus (womb)- is also an incredible shape-shifting organ. Typically only about the size of your fist, its muscular structure will stretch to accommodate a fully grown baby person. It is made of three layers- the inside layer (endometrium), muscular middle layer (myometrium), and outer most layer (perimetrium). The end closest the outside of the body contains the cervix (which opens up into the vagina, see above) and the other end is wider and sits inside the body, low in the pelvis, between the bladder and the rectum. The body of the uterus (fundus) has two small openings on either side, which open into the fallopian tubes.
When reproduction goes perfectly, the sperm makes its way from the vagina through the cervix into the uterus and into the fallopian tubes to the egg that has been released from the ovary and swept up into the tube during ovulation. Once the fertilization of the egg by the sperm has taken place, the zygote (early embryo) makes its way through the fallopian tube into the uterus where in time it implants into the inner most lining of the uterus, a sac forms around the embryo, which grows into a fetus and a placenta will form, which is the conduit from the fetus to the mother’s blood stream and provides nutrients and eliminates waste.There are many parts to this process, and sometimes for successful reproduction to occur, we use the aid of fertility treatments (Intrauterine insemination (IUI), In Vitro Fertilization (IVF), etc—more on this in a later post).
The uterine lining builds up every month in anticipation of an embryo implanting. If there is no embryo, it will shed this lining, or ‘slough off,’ and this uterine blood travels through the cervix out into the vagina. Menstruation occurs on a monthly cycle from age of first menses (around 12 years old) through menopause (around 50 years old). There are MANY things that effect the length, intervals/frequency, the amount of bleeding, and discomfort of the menstrual cycle. Most of these things are benign (non cancerous) but the symptoms can be troubling and can also complicate fertility efforts- things that range from ovulation abnormalities or ovarian cysts, hormonal irregularies, uterine fibroids and polyps and endometriosis (uterine cells outside of the uterus), among others. Of course general health and birth control play a big role in menstrual cycles, also. There is much to be said on all of these topics and it will be posts for another time. Suffice it to say, there is a large variance in cycles from woman to woman. A ‘normal cycle lasts anywhere from 21-35 days and menstruation lasts from 2-7 days. Please see your provider if you are concerned about your menstrual cycle.
Again, a reminder that once ovulation has stopped with menopause, the lining of the uterus will no longer need to shed and menstrual cycles will stop. If you have not had a period for 12 full months and then you have any signs of vaginal bleeding, you need to see your provider immediately as it may be a sign of uterine (endometrial) cancer. This is another reason that we recommend continuing your annual exams after menopause.
Ligaments- there are multiple ligaments inside the pelvis that suspend the cervix and uterus in place and provide support. These ligaments can be stretched during pregnancy and it can be painful. They can also be taxed over time, especially during pregnancy and deliveries and sometimes are weakened and allow the uterus, bladder, or bowel to start to bulge into the vagina. This can impact the ability to urinate or defecate and can be very uncomfortable. Please see your provider if you have any concerns that this is happening to you. Urinary incontinence is also a very common, but extremely uncomfortable condition that many women face. Even just a small leak is abnormal and can negatively affect your life. Please inform your provider of any incontinence issues.
Ovaries: these are tiny organs that produce female sex hormones and are responsible for developing and releasing the ovum (egg) each month in about the middle of the menstrual cycle (unless you’re preventing this with hormonal birth control). There is an ovary on each side of the pelvis, attached to the pelvic wall by a ligament, and they are each about the size of a large olive. Although these are pretty small and deep within your pelvis, some women can feel when they ovulate (the egg is released) and have some discomfort with this around the middle of their cycle, usually distinct and brief and on one side or the other. Many women also have ovarian cysts. Ovarian cysts can range in size, type, and significance. Some are simply related to ovulation and will resolve on their own quickly, others might require monitoring or intervention and might cause changes in cycles, infertility, or pain. Ovaries are examined by bimannual examination during your annual GYN exam and any signs of change in your ovaries will likely be followed up by ultrasound. Your age, personal and family health history, and certain blood tests can help us determine the risk for ovarian cancer. This is still a difficult cancer to diagnose and it is too often found after it has already started to grow, so please get your annual exams and notify your provider of ongoing pelvic, abdominal, or back discomfort or bloating, unplanned weight changes or decreased appetite, or abnormal menstruation.
Fallopian tubes: attached to the sides of the uterus deep in the body, these tubes have little finger-like projections on the end (fimbriae) that sweep near the ovaries and, if ovulation occurs, can catch the egg and sweep it into the tube for fertilization and then implantation to occur. The destruction or removal of fallopian tubes is a method of permanent sterilization. Recently studies have shown that some female pelvic cancer is originating in the fallopian tubes, so many Ob/Gyns (all in our practice) have started removing them once they are no longer actively needed- during hysterectomies or instead of tubal ligations. Tubes can also be the sites of cysts and infections, and will be studied in cases of fertility concerns.
This is a lot of information, and there is so much more we can discuss on any of these organs of the pelvis and the conditions associated with them. If you have general questions about anatomy or pathology, please message us here. If you have specific questions/concerns regarding your anatomy, please contact your Oakland Macomb provider to discuss.
Thank you and be well!