The physiology of sexual arousal in the XXXX female: a recreational and procreational synthesis.

@entity1 @entity26 @entity12179 @entity1613 @entity250
Changes induced by @entity1 sexual arousal serve reproductive and recreational functions. The current sexual phase model (desire, excitation, orgasm, and resolution) conveys little about this duarchy. Lack of spontaneous sexual desire in a third of nonclinic females indicates that the D phase needs splitting into D1 (the spontaneous [endogenous] activation of desire) and D2 (desire activated by sexual excitation at and during the E phase). Attempts to link D1 with reproduction by studies monitoring it over the menstrual cycle revealed a D1 peak just before or at ovulation, but its reliability is criticized because of the poor identification of the time of ovulation. Sexual arousal initiates enhanced genital blood flow, leading to the formation of a neurogenic transudate, lubricating the vagina, partly buffering its acidity, and increasing its @entity26 tension all features that enhance spermatozoal function and survival. Orgasm occurs with vaginal and uterine contractions. The latter have been misinterpreted as powering rapid sperm transport to facilitate fertilization, but such fast transport would lead to the tubal deposition of noncapacitated, incompetent @entity12179 . Vagino-cervico elevation, however, delays rapid sperm transport and allows the @entity1613 and sperm capacitation before the elevation resolves. The fastest transport of @entity12179 from cervix to the fallopian tubes occurs in the nonaroused female by uterine/subendometrial smooth muscle peristalsis. There is some evidence that even this may be reduced for a time after coitus, adding to the transport delay. If a number of the changes induced by sexual arousal are inadequately expressed, @entity250 could arise.
