Cervix and Vagina

Vagina Location

The vaginaThe muscular canal connecting the uterus to the external genitalia. can be found between the urethraThe tube that carries urine from the bladder to the outside of the body. and the rectumThe final section of the large intestine, where feces are stored before elimination.. The urethra is actually bound to the anteriorThe front of the body or toward the front when standing in the anatomical position. wall of the vagina. This connection causes issues for women later in life. This is especially true for those who have had a few babies.  Although the uterusThe muscular organ where a fertilized egg implants and develops. tips anteriorly, the vagina is tilted to the posterior.  The vagina has several major functions. It receives the penis during copulation. It provides an ejection route for the birth of a baby. It also allows the discharge of menstrual fluid.  The vagina is the opening that ultimately leads to the uterus and all the stuff it contains (like a baby). 

Vagina Layers

The vagina, like the stomach, has rugaeFolds in the stomach lining that allow expansion when food enters. which are large folds that are able to expand.  During copulation when the vagina receives the penis, these rugae  expand.  A fornix is this little area right here that is created by the cervix descending into the vagina.  The vagina has its own muscularis, separate from that of the uterus.  The vagina is also contained in its own serosa, separating it from the other items in the abdomino-pelvic cavity.

Vagina Epithelium

The vagina is lined with stratified squamous epithelium.  This is somewhat keratinized since the vagina is open to the outside.  We’ve seen this stratified squamous tissue at many openings such as the mouthThe opening of the digestive tract where food enters and mastication begins. and the anusThe terminal opening of the digestive tract through which feces are expelled..  The stratified cellsThe basic structural and functional units of life. allow for cells to be scraped off without damage to the tissue overall.  There are no glands in the vagina, although there are mucus cells scattered in the mucus membrane of the vagina.  The vaginal walls secrete a very acidicA solution with a pH below 7, having a higher concentration of H⁺ ions. mucus and also receive some cervical mucus via seepage.

Cervix

The cervix is the inferiorBelow or toward the lower part of the body. portion of the uterus that sticks down into the vagina.  The epithelium of the cervix is complicated because it is the transition zone from the uterus to the vagina. One characteristic of the cervix is the production of a lot of mucus.  You can even see some of that mucus balling up here on the apical surface of the cells.  This cervical mucus thins and thickens during the menstrual cycleThe monthly cycle of changes in the female reproductive system. and can be used as an indicator of fertility. 

Around the time of ovulationThe release of a mature oocyte from the ovary., the cervical mucus thins out.  The hope is that after fertilization, there will be a copulatory events leading to the union of sperm and egg.  The thinning of the mucus helps the sperm swim more easily through the fluids. This allows them to ultimately reach the uterine tubesAlso called fallopian tubes, they transport the oocyte to the uterus.. 

A few days after ovulation, the cervical mucus begins to thicken under the influence of progesteroneA hormone that supports pregnancy and regulates the menstrual cycle. from a corpus luteum.  The thickening is a way to ensure that the developing embryo will not have competition.  The thicker mucus makes it harder for sperm to swim to the uterine tubes. It becomes difficult for them to meet up with an ovulated ovumA mature egg cell.  This prevents a second pregnancy from happening.  This is also the basis of progesterone only birth control.  Progesterone thickens the cervical mucus.  As long as you take the pill every day with no exceptions, the cervical mucus will remain thick.  If you miss one day, that cervical mucus plug will degrade and you will have to make another one.

Cervical Cancer

Cervical cancer is more common than you could know. Luckily, there is a really easy way to get checked for cervical cancer every year. There is also another way to check for it every other year. Nowadays, women are recommended to have a pelvic exam every year. This exam lets a gynecologist visualize the cervix. They can check for what you see here in these pictures of the cervix. Every other year, women are recommended to get a pap smear done. This is a simple scraping of cells from the cervix. These cells are stained with a very specific combination of stains called the Papanicolaou stain. This method lends its name to the pap smear. Cells of the cervix should all look the same and take of the stain the same way. The picture on the left shows that. The picture on the right shows cells with no uniformity and very different staining properties.