Chapter 6 Sexual Arousal and Response

Sexual Arousal The role of hormones Steroid hormones testosterone: male sex hormones produced by testes, adrenal glands, & ovaries estrogen: female sex hormone produced by ovaries & testes Neuropeptide hormones oxytocin

Sexual Arousal (cont.) Hormones in male sexual behavior testosterone and desire castration research androgen-blocking drugs hypogonadism hormones in female sexual behavior estrogen and ERT positive correlation between testosterone & frequency of activity

Sexual Arousal (cont.) The role of hormones how much testosterone is necessary? two forms of testosterone testosterone and libido "critical mass" varies excessive testosterone can harm both sexes over time testosterone replacement therapy oxytocin and sexual response

Sexual Arousal (cont.) Table 6.1 Common signs of testosterone deficiency.

Sexual Arousal (cont.) The brain cerebral cortex (mental events) limbic system affects feeling & behavior cingulate gyrus amygdala hypocampus hypothalamus neurotransmitters

Sexual Arousal (cont.) Fig. 6.1 The limbic system, a region of the brain associated with emotion and motivation, is important in human sexual function. Key structures, shaded in color, include the cingulate gyrus, portions of the hypothalamus, amygdala, and the hippocampus.

Sexual Arousal (cont.) The senses touch is the dominant "sexual sense" primary erogenous zones secondary erogenous zones vision is usually next in dominance self-report: males more than females equal physiological signs of arousal

Sexual Arousal (cont.) The senses smell may arouse or offend exposure to a human pheromone increases attractiveness ratings taste plays a minor role hearing plays a variable role

Sexual Arousal (cont.) Aphrodisiacs food alcohol and other drugs yohimbine role of expectations

Sexual Arousal (cont.) anaphrodisiacs drugs: e.g.,opiates, tranquilizers antidepressants and antipsychotics birth control pills nicotine constricts blood vessels, slows vasocongestive response; reduces circulating testosterone

Sexual Response Kaplan's three-stage model desire: distinct, but not required excitement orgasm

Sexual Response (cont.) Fig. 6.2 Kaplan’s three-stage model of the sexual response cycle. This model is distinguished by its identification of desire as a prelude to sexual response. Source: Kaplan 1979.

Sexual Response (cont.) Masters & Johnson's four phases Physiological sources of arousal Problems: simplified too literal interpretation of plateau stage not to be used as a personal standard

Sexual Response (cont.) Two basic processes Vasocongestion Myotonia

Sexual Response (cont.) Masters & Johnson's four phases Excitement Plateau Orgasm Measuring female orgasm with MRI Resolution Refractory

Sexual Response (cont.) Table 6.3 At a Glance Major Physiological Changes During Each of the Four Phases of the Sexual Response Cycle

Sexual Response (cont.) Fig. 6.5a Major changes in external and internal male sexual anatomy during the sexual response cycle.

Sexual Response (cont.) Fig. 6.5b Major changes in external and internal male sexual anatomy during the sexual response cycle.

Sexual Response (cont.) Fig 6.5c Major changes in external and internal male sexual anatomy during the sexual response cycle.

Sexual Response (cont.) Fig. 6.5d Major changes in external and internal male sexual anatomy during the sexual response cycle.

Sexual Response (cont.) Fig. 6.5e Major changes in external and internal male sexual anatomy during the sexual response cycle.

Sexual Response (cont.) Fig. 6.6a Major changes in the external female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.6b Major changes in the external female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.6c Major changes in the external female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.6d Major changes in the external female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.6e Major changes in the external female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.7a Major changes in the internal female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.7b Major changes in the internal female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.7c Major changes in the internal female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.7d Major changes in the internal female genitals during the sexual response cycle.

Sexual Response (cont.) Fig. 6.7e Major changes in the internal female genitals during the sexual response cycle.

Sexual Response (cont.) Orgasm issues Grafenberg spot area on lower front wall of vagina sensitive to pressure sometimes results in “ejaculation”

Sexual Response (cont.) Fig. 6.9 Locating the Grafenberg spot. Usually two fingers are used, and it is often necessary to press deeply into the anterior wall of the vagina to reach the spot.

Sexual Response (cont.) Fig. 6.8 Changes in the breasts during the sexual response cycle.

Sexual Response (cont.) Aging & the sexual response cycle older women decreased vaginal lubrication; is slower decreased flexibility of inner vagina more rapid resolution

Sexual Response (cont.) Aging & the sexual response cycle older men lengthened time to erection loss of "ejaculatory inevitability" more rapid resolution & longer refractory period (hours to days)

Sexual Response (cont.) Some differences between the sexes greater variability in female response male refractory period females can have multiple orgasms