13.9: Female Sexual Activity
- Page ID
- 84100
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)The sequence of changes during female sexual activity can be divided into phases that resemble the phases seen in men. However, female sexual activity involves only the first four of these phases because women can pass from the resolution phase into another excitement phase without an intervening refractory period. Many women can even cycle between the plateau and orgasmic phases several times before entering a resolution phase. In addition and in contrast to the male system, the female system can perform its reproductive role without undergoing the changes involved in female sexual activity. If ovulation and endometrial development have occurred, all that is required for reproduction to begin is the placement of sperm cells into the female reproductive system.
Several changes occur during female sexual activity in young adult women (Table 13.2). These physical changes are accompanied by pleasurable sensations that vary in nature and degree from person to person and from one sexual experience to another. The intensity of these pleasurable sensations usually increases from the beginning of the sexual experience through much of the orgasmic phase and then subsides during the resolution phase.
This section is based largely on the work of Masters and Johnson. The previous comments on heterogeneity in sexual activity in men apply to sexual activity in women. Therefore, the age-related changes in female sexual activity described below represent typical alterations.
Excitement Phase
Erection of the nipples and lubrication of the vaginal lining are the first signs of sexual arousal and mark the beginning of the excitement phase. The lubricating fluid in the vagina eases entry of the penis and neutralizes some of the vaginal acids to prevent damage to sperm cells. Substantial nipple erection and vaginal lubrication may be achieved within seconds after sexual stimulation begins. Both conditions persist and may increase throughout the excitement and plateau phases.
Nipple erection and vaginal lubrication are quickly followed by changes in the clitoris and labia minora. Swelling of the labia minora, which results from an increased input of blood, causes the labia minora to double or triple in thickness and push outward. In so doing, they separate the labia majora and protrude from between them. Simultaneously, changes in the labia majora cause further separation, making the vaginal opening more accessible. Swelling of the breasts results from an increase in blood flow.
As the excitement phase progresses, the inner portion of the vagina opens. This change and others in the vagina, uterus, and glands seem to further prepare the vagina for the entry of the penis. Other changes occur toward the end of this phase.
Plateau Phase
Movement of the clitoris marks the transition from the excitement phase to the plateau phase. If flushing of the skin occurs, it may spread over more of the body. The changes in the vagina and labia minora result from increases in blood flow into these structures. Once these changes have occurred, the orgasmic phase is imminent.
Orgasmic Phase
The orgasmic phase begins with rhythmic contractions of the outer portion of the vagina. As happens during ejaculation in men, the first few contractions are the strongest and occur at intervals of slightly less than 1 second. After the first few contractions, the rhythm slows and the force of contraction diminishes. Vaginal contractions, which may number a dozen or more, are often accompanied by extreme levels of pleasant sensations.
Resolution Phase
As the vaginal contractions of the orgasmic phase subside, the resolution phase begins. The changes that occurred during the previous three phases are reversed, starting with the ones that began last. Thinning of the outer region of the vagina and fading of the color of the labia minora occur within a few seconds. Many seconds to several minutes may be required to completely reverse other changes and fully reestablish resting conditions. However, if sexual stimulation continues or is repeated any time after the orgasmic phase, restoration of resting conditions may cease. The changes of the excitement and plateau phases may then be repeated, and another orgasmic phase may occur.