Sexuality 4: The Sexual Response Cycle

The Sexual Response Cycle

Stage 1: Desire

Fantasy, memory, or sensual stimuli can create sexual desire—a strong wanting for sexual stimulation. Societal and cultural values influence the range of stimuli that provoke sexual desire. Each individual reacts to sets of stimuli that are idiosyncratic—based on his or her own thoughts, feelings, and experiences.

Indications of Desire. Desire is a prelude to sexual excitement and sexual activity—it occurs in the mind rather than the body and may not progress to sexual excitement without further physical or mental stimulation.

Stage 2: Excitement (arousal)

Excitement is the body’s physical response to desire. For both sexes, initial physical excitement may be lost and regained many times without progression to the next stage.

Indications of Excitement:

For both sexes: Heart rate and blood pressure increase, body muscles tense, sexual flush occurs, nipples become erect, genital and pelvic blood vessels become engorged, and involuntary and voluntary muscles contract.
For women: The vagina lengthens and widens, the clitoris swells and enlarges, breasts increase in size, the labia swell and separate, the vagina becomes lubricated and the uterus rises slightly. Vaginal lubrication is the key indicator of sexual excitement.
For men: The penis becomes erect, the scrotum thickens, and the testes rise closer to the body. Erection of the penis is the key indicator of sexual excitement.

Stage 3: Plateau

If physical or mental stimulation (especially stroking and rubbing of erogenous zones or sexual intercourse) continues during full arousal, the plateau stage may be achieved. This stage may be achieved, lost, and regained without orgasm.

Indications of the Plateau Stage:

For both sexes: Breathing rate, heart rate, and blood pressure further increase, sexual flush deepens, and muscle tension increases. There is a sense of impending orgasm.
For women: The clitoris withdraws, the Bartholin’s glands lubricate, the areolae around the nipples become larger, the labia continue to swell, the uterus tips to stand high in the abdomen, and the “orgasmic platform” develops (that is, the lower vagina swells, narrows, and tightens).
For men: The ridge of the glans penis becomes more prominent, the Cowper’s glands secrete preejaculatory fluid, and the testes rise closer to the body.

Stage 4: Orgasm

During orgasm, the peak of the plateau phase, the sexual tension that has been building throughout the body is released, and the release of body chemicals (endorphins) causes a sense of well-being. Women are capable of multiple orgasm (moving immediately from orgasm back into the plateau stage and to orgasm again), whereas men must pass through the resolution stage before another orgasm can be achieved.

Indications of Orgasm:

For both sexes: Heart rate, breathing, and blood pressure reach their peak, sexual flush spreads over the body, and there is a loss of muscle control (spasms).
For women: The uterus, vagina, anus, and muscles of the pelvic floor contract five to 12 times at 0.8-second intervals.
For men: Ejaculation (contractions of the ejaculatory duct in the prostate gland that cause semen to be ejected through the urethra and penis) occurs, and the urethra, anus, and muscles of the pelvic floor contract three to six times at 0.8-second intervals.

Stage 5: Resolution

Resolution is the period following orgasm, during which body muscles relax and the body begins to return to its preexcitement state. Immediately following orgasm, men experience a refractory period, during which erection cannot be achieved (the duration of this period varies among individuals and increases with age). Women experience no refractory period—they can either enter the resolution stage or return to the excitement or plateau stage immediately following orgasm.

Indications of Resolution:

For both sexes: Heart rate and blood pressure dip below normal, returning to normal soon afterward; the whole body (including the palms of hands and soles of feet) sweats; there is a loss of muscle tension, increased relaxation, and drowsiness.
For women: Blood vessels dilate to drain the pelvic tissues and decrease engorgement; the breasts and areolae decrease in size; nipples lose their erection; the clitoris resumes its prearousal position and shrinks slightly; the labia return to normal size and position; the vagina relaxes; the cervix opens to help semen travel up into the uterus (closing 20–30 minutes after orgasm); and the uterus lowers into the upper vagina (location of semen after male orgasm during penile-vaginal intercourse).
For men: Nipples lose their erection; the penis becomes softer and smaller; the scrotum relaxes, and the testes drop farther away from the body. Depending on a number of factors (including age), the refractory period in men may last anywhere from five minutes to 24 hours or more.