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 ?!?