Transcript Chapter 6 Sexual Arousal and Response

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
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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?
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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
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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
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food
alcohol and other drugs
yohimbine
role of expectations
Sexual Arousal (cont.)
• anaphrodisiacs
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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
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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