1. Chapter 4 Similarities and Differences in Our Sexual Responses
For use with the text,
Human Sexuality Today,
5th edition.
Bruce M. King
Slides by Callista Lee
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

2. Measurement of sexual responses
Masters & Johnson recorded over 10,000 sexual episodes leading to orgasm in the 1960’s:
Volunteers aged 18 to 89 years old.
Masturbation, sexual intercourse, oral-genital sex
Measurements included heart rate, blood pressure, muscle tension, respiration and brain waives.
Penile strain gauges and vaginal photo-plethysmographs measured sexual arousal.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

3. Models of sexual response
Masters & Johnson – four phases
Excitement, Plateau, Orgasm, Resolution
Helen Kaplan – three phases
Desire, Excitement, Orgasm
Feminist Scholars – Questioning the focus on just the genitals
Women’s sexual responses are more complex
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

4. Men’s sexual response cycle
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

5. Desire and excitement in males
Erection of the penis, caused by vasocongestion of the spongy tissues within the penis, is the first physical sign of arousal.
Myotonia – a buildup of energy in nerves and muscles.
Increase in heart rate and blood pressure.
The scrotum thickens and spermatic cord shortens, elevating the testicles.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

6. Neural mechanisms of erection
A reflex center low in the spinal cord receives input caused by stimulation to the penis – smooth muscles of the penis then relax, allowing for vasocongestion.
A 2nd erection center receives input from the brain.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

7. King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall
Plateau Phase
High sexual arousal or varying lengths of time.
Penis and testicles become larger.
Cowper’s glands secrete a clear fluid to make the urethra less acidic (from urine).
25% of men experience a sex-tension flush on the skin of the chest or other areas.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

8. Sexual response – inside and out
Changes during the Excitement Phase
The Plateau Phase
The Orgasm phase
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

9. Male orgasm is a rhythmic process
Intense physical sensation and pleasure
Emission stage
Contractions of vas deferens, prostate gland, and seminal vessicles mix sperm with seminal fluids. Feelings of “I’m coming.”
Expulsion (ejaculation) stage
The urinary bladder is closed off from the urethra.
Muscles in the urethra and at the base of the penis contract, forcing the blended semen out of the body.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

10. King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall
Male resolution phase
Resolution is the return to the unaroused state.
Physiological responses drop below the plateau levels and into the excitement level
If stimulation continues, he may return to plateau and another orgasm after a “Refractory Period” during which he cannot experience another orgasm.
Length of the Refractory Period depends on many physiological, behavioral, emotional and age-related factors.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

11. Women’s Sexual Responses
Differences in desire between men and women
Several researchers have concluded that men tend to have higher levels of desire, linked closely to biological factors.
In women, sexual desire is closely linked to relationship and intimacy needs such as feeling valued, nurturance, relief from stress, procreation, pleasure, personal power and feeling the power of one’s partner
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

12. Excitement (arousal) in women – a precedent to feelings of pleasure
Vasocongestion of the vaginal walls causes vaginal lubrication by a “sweating” effect after several minutes of stimulation.
Labia become engorged and move apart.
Walls of the vagina balloon out.
Cervix and uterus pull upward.
Engorged clitoris becomes more prominent.
The nipples erect and breasts plump up.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

13. An inside view of the aroused woman
Early Excitement Phase
Plateau Phase
Orgasm Phase
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

14. The female plateau phase
Inner 2/3 of the vagina expand, uterus tilts further, creating the “orgasmic platform.”
Outer 1/3 of the vagina is highly engorged, very sensitive and significantly narrowed.
50 – 75% experience a sex flush of the skin.
Clitoris pulls back beneath the clitoral hood.
Areola of the breast swells.
Secretion of vaginal lubrication may slow.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

15. Female sexual response, outer view
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

16. Female orgasm and resolution
Subjective feelings of orgasm do not differ from the man’s except for a lack of “orgasmic inevitability” he feels during his emission stage.
Some women experience true multiple orgasms; full orgasms in quick succession without dropping below the plateau levels of physiological arousal (no refractory period).
Focus on orgasm as a goal is self-defeating.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

17. Female variability in sexual response
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

18. Female genital mutilation
Sunna circumcision and excision (80%)
Infibulation (phraonic circumcision)
Village women perform the surgery on girls with primitive tools and without anesthetic.
These patriarchal cultures seek to eliminate female sexual desire so as to reduce infidelity to secure a husband’s ownership of his wife and children.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

19. Controversies about orgasms
5 – 10% of women never have orgasms
About 1/3 of women do not have orgasm during sexual intercourse; of those who do, most require simultaneous clitoral stimulation.
Regardless of the type of stimulation needed to achieve orgasm, physiologically and orgasm is an orgasm.
Biology and psychology affect subjective feelings of intensity and pleasure.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

20. Grafenberg spot & female ejaculations
The G-spot, clearly identified in only 10% of women; highly sensitive dime-sized area on the front vaginal wall, under the bladder. It swells when stimulated.
% of women have experienced ejaculation of the Skene’s glands, usually in women with strong PC muscles and responsive to G-spot stimulation.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

21. Men and multiple orgasms
According to the Masters and Johnson model, men may have several “mini-orgasms” by withholding ejaculation before having a full “wet” orgasm. The wet orgasm is nearly always followed by a refractory period.
Variability among individuals must be considered; some men may experience a wet orgasm followed by “dry” orgasms.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

22. Penis size, attitudes and pleasure
Women rarely mention penis size as a significant factor in their ability to experience sexual pleasure with a man.
X-rated entertainment worships Priapus, leading many normal men to feel insecure.
Despite popular mythology, no study has found a substantial difference in penis size between black men and white men.
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

23. Aphrodisiacs and Anaphrodisiacs
Foods that resemble genitals – placebo effect
Spanish fly – painful inflammation can result
Alcohol – fewer inhibitions but decreased performance
Cocaine – energy, self-confidence, erectile failure and difficulty reaching orgasm
Marijuana – increased tactile sensitivity, erectile problems, lower testosterone levels
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

24. More about supposed aphrodisiacs
XTC (MDMA) – euphoria, overheating, memory loss, permanent brain damage
“Sextasy” – Viagra plus XTC – pounding headaches, prolonged and painful erections
Yohimbine – helpful for men with psychologically caused impotence but little effect on men without erectile problems
Pheromone perfumes – no reliable results
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall

25. People with disabilities
Sexual self-esteem
Creativity and openness to finding behaviors for sexual expression
Understanding partners and care-givers
Emotional intimacy
Regardless of what we look like or our physical or mental capabilities, we are all sexual beings
King, Human Sexuality Today, 5/e (c) 2005 by Prentice Hall