1. The Physiology of Sexual Response
Chapter 9
The Physiology of Sexual Response
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2. Masters and Johnson Four stages of sexual response: Excitement Plateau
Orgasm
Resolution
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3. Masters and Johnson
Two basic physiological processes that occur during these stages:
Vasocongestion
Myotonia
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6. Excitement
Vasocongestion occurs - accumulation of blood in the blood vessels of a region of the body
Vagina lubricates, glans of clitoris swells, nipples become erect
Sex flush may appear
Increase in pulse rate and blood pressure
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8. Plateau Vasocongestion reaches its peak
In females the orgasmic platform forms - tightening of the entrance to the vagina
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9. Orgasm
In males, orgasm consists of a series of rhythmic contractions of the pelvic organs at 0.8 second intervals
In males and females there is a sharp increase in pulse rate, blood pressure, and breathing rate
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10. Resolution Body returns to the unaroused state
Phase takes about 15 to 30 minutes
Gradual return of pulse rate, blood pressure, and breathing rate to the unaroused levels
Refractory period - time during which men are incapable of being aroused again, have an erection, or have an orgasm
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12. Copyright © The McGraw-Hill Companies, Inc
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13. Other Findings of the Masters and Johnson Research
Clitoral orgasm versus vaginal orgasm
Multiple orgasm - a series of orgasms occurring within a short period of time
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14. Cognitive-Physiological Models
Kaplan’s Triphasic Model:
Sexual desire
Vasocongestion
Muscular contractions
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15. Walen and Roth: A Cognitive Model
Perception
Evaluation
Arousal
Perception of arousal
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17. Hormonal and Neural Control of Sexual Behavior
The brain, spinal cord and sex
Spinal reflexes
Three components of a reflex:
Receptors
Transmitters
Effectors
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19. Mechanism of Erection Erection is produced by a spinal reflex
It can also be produced by tactile stimulation of the genitals, and fantasy
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20. Mechanism of Erection
Mechanism of Ejaculation - ejaculation center is located higher in the spinal cord than the erection reflex
Retrograde ejaculation - a condition in which orgasm in the male is not accompanied by an external ejaculation
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22. Mechanisms in Women Female ejaculation
Grafenberg spot - small region on the front wall of the vagina, emptying into the urethra, and responsible for female ejaculation
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24. Brain Control of Sexual Response
Limbic system - set of structures in the interior of the brain, including the amygdala, hippocampus, and fornix; believed to be important for sexual behavior in both animals and humans
Sex centers or pleasure centers
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26. Hormones and Sex
Organizing effects - effects of sex hormones early in development, resulting in a permanent change in the brain or reproductive system
Activating effects - effects of sex hormones in adulthood, resulting in the activation of behaviors, especially sexual behaviors and aggressive behaviors
Testosterone and sexual desire
Testosterone has effects on libido in males
Androgens are related to sexual desire in women
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27. Pheromones
Biochemicals secreted outside the body that are important in communication between animals and that may serve as sex attractants
May play an important role in sexual behavior
Menstrual synchrony - convergence, over several months, of the dates of onset of menstrual periods among women who are in close contact with each other
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