The vaginal epithelium is the tissue lining the inside of the vagina in humans and other animals. Like most other tissue, it has specialized structures and functions. Although not precisely the same as skin, it shares many characteristics with skin and connects with the skin at the entrance to the vagina. This lining is composed of cells with a unique structure. Doctors specializing in the female reproductive system can examine these cells for evidence of disease or infection that can affect the overall reproductive tract.
Epithelium is a kind of tissue found throughout the body, both internally and externally. Epidermis, or skin, is one kind of epithelium. Other kinds form the linings of blood vessels, intestines, and various other organs and orifices. Vaginal epithelium extends the length of the vagina, from its opening at the vulva to the cervix, where it is replaced by cervical and ovarian epithelium. These forms of epithelium have their own structure and functions, distinct from that of the vagina.
Vaginal epithelium is specially constructed to allow the unique functions of the vagina and the reproductive system to occur. It is composed of many layers of cells so that injury does not result if the outermost layers are removed by friction, for example during intercourse or menstruation. Unlike external skin cells, these cells allow for the passage of moisture, enabling the natural lubrication that occurs during intercourse and sexual stimulation. These cells, combined with the unique muscular structure of the vagina, also allow the organ to expand in size, as required during sexual intercourse or childbirth.
Doctors specializing in the female reproductive system, called gynecologists, are required to familiarize themselves with the normal appearance of vaginal epithelium and its cells. Abnormalities in these cells can indicate diseases such as cancers. A procedure called a Pap test, or Pap smear, collects a sample of these cells for close examination. This can reveal health conditions that may lead to cervical cancer. This is an extremely dangerous disease, and consequently adult women are advised to undergo the Pap smear on a regular basis as part of their overall reproductive health regimen.
A multitude of other diseases can also be indicated by irregularities in the vaginal epithelium. Women who suspect such irregularities should consult a specialist in gynecological medicine. It should also be noted that not all vaginas contain this form of epithelium. Women with artificial vaginas, resulting from sexual reassignment surgery, will not have vaginal epithelium. These vaginas are usually constructed with tissue from elsewhere in the patient’s body during the reassignment process and will not be lined with the specialized vaginal cells of those born biologically female.