Vagina

The vagina serves several purposes. As the tubular and muscular organ that is most prominent of all the sex organs, it is designed to receive spermatozoa as well as to provide a passage for the birth of baby. This fibromuscular organ also serves as the passageway for the release of bodily fluids during menstruation. Measuring at about 9 cm long, it reaches from the vaginal vestibule to the cervix. Anterior to the rectum and posterior of the urinary bladder, the vagina creates a continuation of the cervical canal located inside the uterus.

The vagina and the cervix create a junction which measure at about 90 degrees. The fornix is the deep recessed region which surrounds the cervical protrusion into the vagina. The exterior lower opening leading to the outside of the body is known as the vaginal orifice. There is a thin mucous membrane which creates a fold which covers in part the vaginal opening. This is deemed the hymen. The vaginal wall is comprised of 3 various and distinctive layers.

The outer layer is the fibrous layer which is responsible for attaching the vagina to the pelvic organs to provide structural support. Strands of elastic like fibers are interfaced with dense connective tissue in order to provide a strong supportive foundation. The vagina is highly vascular and requires a great deal of blood which is supplied for the most part from the vaginal branches of the internal iliac artery. Additional arteries such as the uterine, middle rectal, and internal pudental arteries also provide additional blood flow via branches. Venous draining happens through the veins of the vagina which run alongside the arteries. The second and third sacral nerves provide the vagina with sympathetic innervation originating from the hypo-gastric plexus as well as parasympathetic innervation. Near the vaginal orifice the pudental plexus provides a high degree of sensory innervation.

Vagina

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The middle layer of the vagina is known as the muscularis layer and contains a few glands. Glands within the uterus present the acidic mucous found in the vagina. Bacteria and other forms of microbes find the 4.0 Ph acidity too uncomfortable for growth in the vagina. Seminal fluid neutralizes this intense acid concentration to be uninhabitable and contains fluids that temporarily allow the semen to survive on order for procreation to occur. Distensible connective tissue which in interlaced with the smooth muscular regions of the muscularis layer. These muscles and the assisting connective tissue create the layer in longitudinal and circular bands of developed tissue. During parturition, the ability for this layer to distended is vital. The vaginal opening is partially constricted via the muscle strands which are determined near the orifice as well as the assistance of skeletal muscle levator ani.

The third layer is the inner mucosal layer of which is comprised of a non-keratinized stratified squamous epithelium which produces vaginal rugea. Vaginal rugae are a succession of crosswise folds. These rugae are responsible for vaginal distention to accept an erect penis and are covered with small ridges for stimulation.