Arousal and Response 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 ?!?