|
Specialists in the Medical & Psychological Aspects of Transgender Health Care |
 |
|
|
| medical/hormonal |
|
|
|||||
|
||||||||||||||||||||||
|
 |
 |
|
Vagina Anatomy The vagina serves as a passage for the exit of menstrual flow, insertion of the penis during sexual intercourse, reception of semen, and the is the birth canal. The vagina is a canal that extends from the vulva to the cervix. The vaginal walls can be easily distended but are normally 7.5 cm in length anteriorly and 9 cm long posteriorly. The upper portion of the vagina encircles the vaginal part of the uterine cervix. The vagina touches the empty bladder on the ventral and superior surface. Inferiorly the vagina adheres to the posterior wall of the urethra and opens into the vestiblule between the labia minora. The vaginal lining has many transverse ridges. Vaginal tissues receive blood supply from uterine areterisa and sometimes branches of the internal iliac artery. Venous return is through veins that empty into the internal iliac veins. Vaginal nerves are derived from the uterovaginal plexus and lymphatic drainage is via the external and internal iliac nodes and superficial inguinal nodes. The levator ani muscles of the pelvic floor provide important support to the vagina and uterus. There are no glands found in the vagina such that all mucous secretions found there are derived from the cervix. Glycogen and aqueous exudates are derived from the vaginal epithelium and blood supply. Histology The vaginal wall is made of three layers: a mucosa, musclular layer and an adventia. Vaginal epithelium is stratified squamous epithelium having a thickness of 15-200 microns. Intense keratinization like that seen in the stratified squamous epithelium of the skin is not seen, although some keratin is found in vaginal epithelium. Estrogen causes the epithelium to thicken, differentiate and accumulate glycogen. This glycogen is found within the vagina when the epithelial cells slough off. Vaginal bacteria metabolize the glycogen to lactic acid, causing the typically low pH of the vaginal environment. Loose connective tissue with many elastic fibers is found underneath the vaginal epithelium. A rich vascular supply is the source for vaginal moisture during sexual stimulation. Vaginal muscle is mostly smooth muscle oriented longitudinally. However, there are some circular bundles. The outer layer, the adventia, is made of dense connective tissue with many elastic fibers, extensive nervous supply and venous capillaries. Vaginal Cycle Cytologic examination of the cells exfoliated from the vagina yields information of clinical importance. In experimental animals, such as the rat, the exact stage of the estrous cycle can be determined by examining vaginal smears. In humans, the ratio of different cell types and their morphology can be used to determine the hormonal status of the patient and can be useful in the early detection of cervical cancer. Vaginal smears during the follicular phase, under the influence of estrogen, contain mostly flattened cells with obvious nuclei that look something like a poached egg. Luteal phase (progesterone predominates) smears contain white blood cells and very flat, cornified cells with reduced nuclei resembling a fried egg. In post menopausal women, the vaginal epithelium becomes very thin, the blood supply to the vagina is reduced, and the cervical glands regress so that the vaginal wall can become weak, dry and itchy. Exogenous estrogen is often prescribed (oral, patch, or cream) to reverse the effects of estrogen withdrawal on the vaginal epithelium. Pathology The vagina can become host to various infectious organisms including bacteria, fungi, protozoa and viral agents, most of which are sexually transmitted diseases. Treatment depends on the causative agent.
|
||||||||||||||||||||||||||||||||||||||||||||||
|
Site
Help
This Site may also be accessed via www.tgcare.com Transgender
Care Health Information Archive
|
