![]() Tracing the emergence of sexual behavior from infancy onward helps us understand how nature and nurture interact. This article began by stating that a developmental perspective on sex is theoretically valuable, and we can now explain why. Baldwin, in Encyclopedia of Human Behavior (Second Edition), 2012 Theoretical Interlude Venous return and lymphatic drainage from the urogenital diaphragm accompany the arterial supply and therefore drains into the internal iliac and femoral veins. Laterally, the external pudendal artery arises from the femoral artery and supplies the lateral aspect of the vulva. The blood supply to the mons pubis originates anteriorly from the inferior epigastric artery, a branch of the femoral artery. On emerging from Alcock canal, the internal pudendal artery sends branches to the urogenital triangle anteriorly. ![]() ![]() The muscles of the urogenital triangle consist of the deep and superficial transverse perineal muscles, paired ischiocavernosus muscles that cover the crura of the clitoris, and bulbocavernosus muscles covering erectile vestibular bulbs that lie on either side of the vaginal introitus.īlood supply to structures within the urogenital triangle is predominantly from a posterior direction from the internal pudendal artery, which, after arising from the internal iliac artery, passes through Alcock canal, a fascial tunnel along the obturator internus muscle below the origin of the levator ani muscle. Beneath the aforementioned external structures lies the urogenital diaphragm, a fascial and muscular shelf extending between the pubic rami and penetrated by the urethra and vagina. The urogenital triangle has its apex anteriorly at the symphysis pubis and its base posteriorly formed by a line drawn between the ischial tuberosities. These external structures are part of the urogenital triangle, which is the anterior portion of the perineum. These glands also produce secretions that provide vaginal lubrication with sexual arousal. Skene glands, homologues of the prostate gland in males, are located to the right and left of the urethral meatus. These glands secrete mucous during sexual arousal to provide vaginal lubrication. Bartholin glands, homologues of the bulbourethral glands in males, are located posteriorly to the right and left of the vaginal introitus. Within the vestibule are Bartholin glands and Skene glands. The vaginal introitus is initially covered by a thin membrane called the hymen, which is usually ruptured by exercise, during insertion of tampons, or during the first episode of intercourse. The labia cover the vestibule, the area of the vulva consisting of the vaginal introitus and urethral meatus, and is demarcated by the Hart line. The labia majora and labia minora are separated by a groove called the interlabial sulci, and the labia minora fuse anteriorly to form the clitoral hood (also known as the prepuce). The lower part of the mons pubis is divided by a fissure named the pudendal cleft, which separates the mons pubis into the labia majora. The mons pubis is the soft fatty tissue covering the pubic bone. The main external structures of the vulva are the mons pubis, the labia majora and labia minora, the clitoral glans and clitoral hood, the urethral meatus, the vaginal introitus and hymen, and Bartholin and Skene vestibular glands ( Fig. Townsend JR., MD, in Sabiston Textbook of Surgery, 2022 External Reproductive Anatomy (Vulva) 11 Metabolic conditions of low inflammation are supportive to the bioavailability of NO in facilitating vaginal lubrication.Ĭourtney M. Many biological feedback mechanisms exist to suppress the production of NO as high production of NO in an inflammatory environment can lead to irreversible free radical production. Importantly, the presence of NO is not sufficient for its effect. The enzymatic function of NO synthase is enhanced by steroid hormones, most notably estrogen in a rapid-action nongenomic effect. Therefore, vaginal lubrication production depends upon the synthesis, enzymatic facilitation, and bioavailability of NO ( Table 59.2). 9 Once produced, NO induces vasodilation through a cyclic guanosine monophosphate (cGMP) cascade, which diminishes as phosphodiesterase enzymes subdue the effect. 4 Gaseous NO is produced in capillary endothelia in response to shear stress or vibration or in response to sexual arousal via parasympathetic nitrergic nerves. Sufficient pelvic blood flow is dependent on the bioavailability of nitric oxide (NO). 7 The resultant vaginal transudate is mainly composed of water and very small proteins, which combine at the vaginal surface with dead epithelial cells. īlood pressure pushes fluid from the capillaries through intracellular gap junctions between vaginal epithelial cells.Vaginal lubrication is reliant upon healthy blood flow because vaginal lubrication is ultrafiltrated blood.
0 Comments
Leave a Reply. |