Chapter 6 Sexual Arousal and Response

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Chapter 6Sexual Arousal and Response
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The Brain and Sexual Arousal

• Cerebral cortex (mental events)
• Reasoning, language, and imagination
• Limbic system and sexual behavior
• Hypothalamus
• Neurotransmitters
• Dopamine facilitates sexual arousal
• Serotonin inhibits sexual arousal

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The Limbic System and Sexual Behavior
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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 and men have similar physiological
  responses

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Other Senses and Sexual Arousal

• Smell may arouse or offend
• Pheromones
• Taste plays a minor role
• Hearing plays a variable role

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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

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Anaphrodisiacs

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

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The Role of Hormones in Sexual Behavior

• Steroid hormones
• Androgens (including testosterone)
• Produced by testes, adrenal glands, and ovaries
• Estrogens
• Produced by ovaries and testes
• Women and men produce both types
• Neuropeptide hormones
• Oxytocin

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Sex Hormones in Male Sexual Behavior

• Testosterone
• Linked to sexual desire and genital sensitivity
• Castration leads to reduced sexual desire
• Antiandrogen drugs
• Hypogonadism

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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

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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 mens
• Too much testosterone is linked to adverse
  effects
• Testosterone levels decrease with age
• Fairly rapid decrease for women at menopause
  more gradual decline for men
• Testosterone Replacement Therapy

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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

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Sexual Response
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Sexual Response

• Masters and Johnsons Four Phases
• Excitement
• Plateau
• Orgasm
• Resolution

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Sexual Response

• Masters and Johnsons Four Phase Model
• Phases of physiological responses
• Two basic physiological processes
• Vasocongestion
• Myotonia

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Sexual Response Cycle
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Female Sexual Response
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Male Sexual Response
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Orgasm

• Shortest phase of sexual response cycle
• Men and womens 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

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Sex Differences in Sexual Response

• Greater variability in female response
• Male refractory period
• Women can experience multiple orgasms

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Locating the Grafenberg Spot
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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

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Aging and the 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

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Age-Related Changes in the Sexual Response Cycle