The vagina belongs to the interior female genitals and is approximately 8 to 10 cm long. The introitus vaginae (vaginal entrance) is narrowed by the hymen, which normally tears during the first sexual intercourse. It is also the border between the exterior and interior genitals of a woman.
Toward the front, the vagina lies next to the bladder and the urethra and borders the rectum. The vagina enfolds the vaginal portion, thus forming the anterior and posterior vaginal vaults. The posterior vaginal vault in particular has clinical significance, as it lies next to the excavatio rectouterina (Douglasâ€™ space), and therefore can be vaginally palpated and punctured. The vagina plays a major role for the diagnostics of cancer diseases (Krukenberg tumor), inflammatory processes (tuboovarial abscess) and also in the differential diagnosis of abortive episodes (extrauterine pregnancy).
The Bartholinâ€™s glands (glandulae vestibulares majores), which lie in the vulva, open out into the vestibulum vaginae enfolded by the labia. They lie directly behind the bulbus vestibuli and under the musculus transversus perinei profundus (deep tranverse perineal muscle). The tubuloalveolar glands secrete a mucous, alkaline fluid, which serves to lubricate the vulva.
The vaginal wall consists of several layers.
The tunica mucosa comprises vaginal epithelium and lamina propria.
It is subject to hormonal influences and therefore shows cyclical changes in sexually mature women. The layers mature under the influence of estrogen, and progesteron. The epithelial layer is relatively loose and enables the passage of lymphocytes and lymph into the vaginal lumen. The epithelium does not contain glands; the "vaginal secretion" consists only of desquamated cells, cervical secretion and transudate of the vaginal wall.
The lamina propria consists of loose connective tissue, which is rich in elastic fibers and lymphocytes. It contains many capillaries, which on sexual arousal secrete a transudate through the epithelium into the vagina, and the plexus venosus vaginalis. The sensitivity of the vagina is low, as there exist only a few free nerve endings, and sensoric fibers are entirely absent.
As a rule, the tunica muscularis is poorly developed and shows thin longitudinal and annular bundles of smooth muscle fibers.
The epithelium cells of the vagina synthesize glycogen, which they release into the vaginal lumen. There it is converted into milk acid by physiological resident lactobacteria, the so-called Doederleinâ€™s bacilli. There exists therefore an acidic ph value of approximately 4.0 in the vagina. It protects the vagina from a colonization of pathogen bacteria and prevents infections.
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