Lighting the fire, Stoking the flame Arousal and Response Lighting the fire, Stoking the flame

The Essential Hormones Two basic types – Steroid & Neuropeptide Steroid Hormones – secreted by the gonads and adrenal glands Examples: testosterone, estrogen, etc. Not simply male or female – both sexes produce each, but in varying amounts

Neuropeptide Hormones Produced in the brain, they influence sexuality and behavior Perhaps the most significant: Oxytocin – the “love hormone”, it influences our erotic and emotional bonds

Testosterone – “the motivator” Men have 20 to 40 times more Effects desire (libido) more than function But deficiencies do decrease sensitivity and desire Castration – the surgical removal of the testes causes dramatic reductions in sexual interest and desire

Testosterone uses

Less Testosterone Antiandrogens – drugs which reduce testosterone levels Occasionally given to sex offenders Usually decreases sexual interest and activity But sometimes offenders assault for other reasons , such as anger, power and control

Hypogonadism – testosterone deficiency due to diseases of the endocrine system If it begins before puberty, development is slowed If it starts after puberty, a marked decrease in desire follows

Estrogens and Desire Their influence is undeniable but exact role is unclear Research findings differ as to whether they increase desire

Females & Testosterone Testosterone clearly increases female sexual desire, sensitivity and activity True even for women after menopause or removal of the ovaries

Women with “normal” levels of sexual activity and hormones who receive additional testosterone show significant increases in sexual arousal, sensation and even lust Theresa Crenshaw “…. when a woman’s testosterone dwindles, so does her sex life.”

More On Testosterone Women have much less testosterone, but are much more sensitive to its effects For women, too much testosterone causes problems, such as “unwelcome” changes to secondary sexual characteristics Women see levels fall more rapidly after menopause than male’s more gradual decline

If measured, it is “free” (unattached) testosterone that matters, not “total” Testosterone Replacement Therapy commonly available for men now, slowly becoming an option for women

Marketing Testosterone

oxytocin A neuropeptide from the hypothalamus that effects sexual response and attraction Bonding occurs through its release mother/child – breast feeding sexual partners – arousal and response Autistic children have low levels and corresponding difficulties forming bonds and expressing love

Oxytocin and Love Release is triggered by touch Its circulation increases the skins sensitivity to touch Levels increase within us as we go through the cycle of arousal to orgasm Presence remains in blood stream after orgasm facilitating pair bonding

The Brain – Our Most Sexual Organ? Our cerebral cortex stores memories and images producing powerful fantasies Our culture has conditioned us to have certain preferences for what we consider physically attractive World-wide prototypes?

Exemplars of Beauty A 2005 poll of plastic surgeons revealed the following as possessing the most desired: Nose – Nicole Kidman Eyes – Catherine Zeta Jones Lips – Angelina Jolie

Nose

Eyes

Lips

The Limbic System A subcortical brain system of several related structures that impact sexual behavior Investigated through a number of studies

Olds (1950’s) Implanted electrodes in rat’s limbic system Allowed them to control stimulation When given the chance, rats will “dial their own number” until they reach exhaustion, even up to several thousand times an hour “pleasure centers”

Heath (1972) Humans with a variety of disorders were allowed to self-stimulate their limbic system One man pushed his button over 1500/hr, described intense sexual pleasure, and complained whenever a “session” ended A woman reported similar experiences, even multiple orgasmic responses

The Hypothalamus Stimulation greatly arouses rats Its destruction crushes response Apparently, the medial preoptic area (MPOA) is especially sensitive Heroin, morphine and other opiates suppress activity of the MPOA Dopamine and testosterone excite it

Serotonin’s Influence Presence inhibits sexual activity Seems to have the opposite effects of dopamine Released after males ejaculate and blocks or dampens sensitivity to dopamine and oxytocin SSRI’s have many negative effects on sexuality

The Senses Many sources of erotic stimulation Their influence leads to tremendous variety and amazing sexual complexity

Touch Our nerve endings are unevenly distributed, locations which are most sexually responsive are called our Primary Erogenous Zones, which include our genitals, lips, buttocks, inner thighs, neck, mouth, perineum But we find tremendous variability

Secondary Erogenous Zones other areas touched within the context of sexual intimacy Could be anywhere on the body Established through classical conditioning?

Vision Very important in our society Emphasis on physical attractiveness, grooming, clothes and cosmetics Are males more aroused by visual stimuli?

Kinsey’s survey said, “YES!” But once women were presented with the: 1) right stimuli, 2) in the right settings, and 3) measured the right way, STRONG similarities between men and women were found though women’s self-reports say no

Smell Are genitals smells arousing or awful? Depends largely on where you live and your acceptance or rejection of fragrance claims.

Pheromones Odors secreted by the body which relate to reproduction Common for mammals The vomeronasal system relates to their use Present in humans, But is it functional?

What Works Smells that arouse Women – licorice, banana nut bread, cucumbers Men – lavender, pumpkin pie, doughnuts

What Doesn’t Women – barbecued meat, men’s cologne’s Men – Nothing

Aphrodisiacs Substances that supposedly increase sexual desire and capacity

Do They Deliver? Many claims – little evidence Alcohol, amphetamines, barbiturates, cocaine and marijuana reduce inhibitions but also sexual response The power of suggestion seems key

Hope on the Horizon? One substance, yohimbine hydrochloride (sap of the tropical evergreen) does increase desire and performance

Anaphrodisiacs Substances which inhibit sexual desire and performance Many things “work” Drugs such as opiates, tranquilizers, and antidepressants inhibit ejaculation and cause erectile problems in males and decrease orgasmic capacity for females

Other Anaphrodisiacs Birth control pills decrease free testosterone levels Nicotine both decreases vasocongestion and reduces testosterone levels

Sexual Response A highly individualized process Research has revealed common patterns of physiological changes

Kaplan’s Three Stages Desire – a prelude to physical sexual response, ignored by Masters and Johnson Excitement Organism

Masters and Johnson Sexology Trailblazers Direct Observation

Masters and Johnson’s Four Phases Excitement both men and women: muscle tension, anatonia increased heart rate/blood pressure engorgement sex flush

More Excitement Women: engorgement lubrication enlargement Men: erection enlargement/elevation

Stage II - Plateau The acceleration of processes begun in the excitement phase Females the orgasmic platform – the significantly engorged outer 1/3 of the vagina Lasts from a few seconds to a few minutes

Phase III - Orgasm Involuntary muscle spasms Blood pressure, respirations, heart rate peaks Males – emission then expulsion

Are the males’ and females’ experiences different ? Descriptions are indistinguishable.

Are some Orgasms superior ? Freud thought so, claiming that vaginal orgasms are more “mature” than clitoral This view, influential for decades, has been abandoned Masters and Johnson established that there is just one kind of female orgasm, though most arise from clitoral stimulation

Return to the “G” Spot Once found, manual stimulation produces variable sensations Intense pleasure and orgasm usually follows Some women even experience ejaculation But the source of the fluid is uncertain

Finally, Resolution Process through which sexual systems return to a nonexcited state While in most respects the sexes experience this process similarly, men go through a refractory period during which they cannot experience another orgasm

Aging and the Response Cycle Function continues but intensity declines Older women – longer for lubrication Occasional decreases in desire, sensitivity, and capacity Older men – longer for erection/orgasm greater control longer refractory period

Where the Sexes Differ Despite surprising similarities, some distinctions remain Variability Women have three patterns within the sexual response cycle Men just one

The Male Refractory Period Why? Evolution based ? Give another guy a chance ? Dependent on midbrain- hypothalamus pathway ?

Multiple Orgasms Women can have several, in succession But just 14 to 16% ? Masters and Johnson say most can have 5-6 ! Men can too ?!?