1. Sexual Arousal and Response

2. 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

3. Sex Hormones in Male Sexual Behavior
Testosterone
Linked to sexual desire & genital sensitivity
Castration leads to reduced sexual desire
Antiandrogen drugs
Hypogonadism

4. 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

5. 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

6. Testosterone Deficiency
Common signs of testosterone deficiency in both sexes

7. 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

8. Sexuality and Diversity
Sexual attitudes and behaviors differ across culture
Behaviors, e.g. kissing, oral sex, foreplay
Erotic arousal, standards for attractiveness

9. The Brain and Sexual Arousal
Cerebral cortex (mental events)
Limbic system and sexual behavior
Neurotransmitters
Dopamine facilitates sexual arousal
Serotonin inhibits sexual arousal

10. The Limbic System and Sexual Behavior
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.

11. 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

12. Other Senses
Smell may arouse or offend
Pheromones
Taste plays a minor role
Hearing plays a variable role

13. 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

14. Some Alleged Aphrodisiacs
Some alleged aphrodisiacs and their effects.

15. Some Alleged Aphrodisiacs
Some alleged aphrodisiacs and their effects.

16. Anaphrodisiacs
Inhibit sexual behavior
Drugs (e.g. opiates, tranquilizers)
Antihypertensives, antidepressants & antipsychotics
Birth control pills
Nicotine
Constricts blood flow
Possibly reduces circulating testosterone

17. Sexual Response
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.

18. Sexual Response
Master’s and Johnson’s Four Phase Model
Phases of physiological responses
Two basic processes
Vasocongestion
Mytonia

19. Sexual Response
Master’s and Johnson’s Four Phases
Excitement
Plateau
Orgasm
Resolution

20. Sexual Response Cycle
Major physiological changes during each of the four phases of the sexual response cycle

21. 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”

22. Sex Differences in Sexual Response
Greater variability in female response
Male refractory period
Women can experience multiple orgasms

23. Locating the Grafenberg Spot
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.

24. 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

25. 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

26. Age-Related Changes in the Sexual Response Cycle
Common changes in the sexual response cycle of older women and men.

27. Breast Changes During the Sexual Response Cycle
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