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Sexual Arousal and Response. Sex Hormones. Steroid hormones Androgens (including testosterone) Produced by testes, adrenal glands, & ovaries Estrogens Produced by ovaries & testes Women & men produce both types Neuropeptide hormones Oxytocin. Sex Hormones in Male Sexual Behavior.
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Sex Hormones • Steroid hormones • Androgens (including testosterone) • Produced by testes, adrenal glands, & ovaries • Estrogens • Produced by ovaries & testes • Women & men produce both types • Neuropeptide hormones • Oxytocin
Sex Hormones in Male Sexual Behavior • Testosterone • Linked to sexual desire & genital sensitivity • Castration leads to reduced sexual desire • Antiandrogen drugs • Hypogonadism
Sex Hormones in Female Sexual Behavior • Estrogens • Overall link between estrogen and female sexual behavior is unclear • Estrogen Therapy (ET) • Testosterone • Role as major libido hormone in females
How Much Testosterone is Necessary? • Two forms of testosterone (free and bound) • Free testosterone linked to libido • Although women have less free testosterone, their cells are more sensitive to it than men’s • Too much testosterone linked to adverse effects • Testosterone levels decrease with aging • Fairly rapid decrease for women at menopause; more gradual decline for men • Testosterone Replacement Therapy
Oxytocin and Sexual Behavior • Secreted during cuddling and physical intimacy • Increased skin sensitivity • High levels associated with orgasmic release for women and men • For women, stimulates contractions of uterine wall during orgasm
Sexuality and Diversity • Sexual attitudes and behaviors differ across culture • Behaviors, e.g. kissing, oral sex, foreplay • Erotic arousal, standards for attractiveness
The Brain and Sexual Arousal • Cerebral cortex (mental events) • Limbic system and sexual behavior • Neurotransmitters • Dopamine facilitates sexual arousal • Serotonin inhibits sexual arousal
The Senses and Sexual Arousal • All sensory systems can contribute to arousal • Touch is the dominant “sexual sense” • Primary erogenous zones • Secondary erogenous zones • Vision usually next in dominance • Visual stimuli • Men self-report higher arousal than women • Women & men have similar physiological response
Other Senses • Smell may arouse or offend • Pheromones • Taste plays a minor role • Hearing plays a variable role
Aphrodisiacs • Substances believed to arouse sexual desire or increase capacity for sexual activity • Food • Drugs and alcohol • Yohimbine • No clear evidence of genuine aphrodisiac qualities • Role of expectations
Anaphrodisiacs • Inhibit sexual behavior • Drugs (e.g. opiates, tranquilizers) • Antihypertensives, antidepressants & antipsychotics • Birth control pills • Nicotine • Constricts blood flow • Possibly reduces circulating testosterone
Sexual Response • Master’s and Johnson’s Four Phase Model • Phases of physiological responses • Two basic processes • Vasocongestion • Mytonia
Sexual Response • Master’s and Johnson’s Four Phases • Excitement • Plateau • Orgasm • Resolution
Orgasm • Shortest phase of sexual response cycle • Men and women’s subjective descriptions of orgasm are similar • Most female orgasms result from stimulation of the clitoris • Grafenberg spot • Area on lower front wall of vagina, sensitive to pressure • Sometimes results in “ejaculation”
Sex Differences in Sexual Response • Greater variability in female response • Male refractory period • Women can experience multiple orgasms
Aging & Sexual Response Cycle • Older women • Response cycle continues, but with decreased intensity • Excitement: Vaginal lubrication begins more slowly, reduced amount • Plateau: decreased vagina flexibility • Orgasm: number of uterine contractions decrease • Resolution: occurs more rapidly
Aging & Sexual Response Cycle • Older men • Response cycle continues, with changes in intensity and duration of response • Excitement: lengthened time to erection • Plateau: able to sustain plateau phase longer • Orgasm: reduced muscular contractions and force of ejaculation • Resolution: occurs more rapidly • Refractory period lengthens