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Chapter 9 Human Sexuality.docx

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Department
Psychology
Course
Psychology 2075
Professor
Prof
Semester
Winter

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Chapter 9: Sexual Response Sexual Response Cycle o 3 stages: excitement, orgasm, resolution o 2 physio processes involved= vasocongestion and myotonia o Vasocongestion= a lot of blood in the vessels of the genitals because of dilation o Myotonia= muscles contract throughout entire body Excitement o Vasocongestion results in erection corpora cavernosa and spongiosum fill with blood o Several arteries dilate and fill, veins carrying blood away compress o Occurs fast in young males but could slow as a result of age, alcohol intake, fatigue o As man gets closer to orgasm= pre-semen at tip from Cowper’s Gland, active sperm o Arteries dilate kuz smooth muscle around them relax o NT’s involved= Nitric Oxide which Viagra acts on o Reverse process vasoconstriction makes erection go away o NT’s= Epinephrine and Norepinephrine o Process occurs in resolution phase o Women= lubrication of vagina from same process vasocongestion o Capillaries dilate o Fluids seep through walls of vagina because of vasocongestion in surrounding tissue o 10-30 sec after stimulation can also be affected by age, alcohol intake, fatigue o Orgasm Platform= when closer to orgasm tightening of bulbospongiosus muscle around vaginal entrance, becomes smaller o Excitement phase tip of clitoris swells, corpora cavernosa swells, larger, harder o Crura of the clitoris also swells deeper in the body and vestibular bulbs (wall of vagina) o Late Excitement Phase elevation of clitoris, breasts swell and enlarge somewhat (vasocongestion) o Estrogen helps vasodilation, swells inner lips and opens them up o Muscle fibres contract to make nipple erect o Upper 2/3rds of vaginal walls expands “ballooning” response cervix and uterus also pull up accommodating penetration o “sex flush”= rash on upper abdomen spreads over chest o men and women= increase blood p/pulse rate o men scrotum thickens, tenses and pulls up by shortening of spermatic cord Orgasm o Men rhythmic contractions 0.8 sec intervals o 2 stages: preliminary stage the vas +seminal vesicles + prostate contract forcing ejculate into base of urethra o feel “ejaculatory inevitability” or cumming, can’t be stopped at this point o second stage urethral bulb + muscles at base of penis + urethra contract forcing semen out tip of penis o males and females= increase of pulse, blood p and breathing rate, face contorted, muscles of arms, legs, thighs, back and buttocks may contract. o Carpopedal spasms—feet and hands o Femles rhythmic contractions .8 sec intervals apart, 3-4 in mild orgasm, 12 in long intense one o no tangible evidence, except for women who emit fluid o often don’t reach orgasm as fast as men do, so young women may think they have had one but havn’t o a spreading sensation starts at clitoris and spreads to whole pelvis, or falling/opening up o sensations are similar for men and women Resolution o after orgasm body returns to unaroused state o Women reduction in breast swelling (5-10 sec) after orgasm, clitoris returns to normal size, orgasmic platform relaxes and shrinks o usually takes 15-30 mins but 1 hour for girls who have never had one o Both males and females return of pulse to normal rate, blood p, breathing rate o Men detumescence—loss of erection o 2 stages= first fast, still larger size, emptying of corpora cavernosa o second stage more slowly, emptying of corpora spongiosum and the glans o Refracory Period= incapable of being aroused, erection, or having orgasm, amount of time varies, becomes longer as men grow older o Women don’t have this, multiple orgasms possible o Oxytocin released during arousal o Prolactin surge at orgasm in men and women—more during orgasm from intercourse then masturbation More on Women’s Orgasms o 2 kinds= clitoral orgasm and vaginal orgasm o Freud thought clitoral orgams were “immature” because little girls he thought masturbated that way and as you mature you switch to vaginal orgams o Affected many women who have been called “vaginally frigid” or “fixated”— who have only had clitoral orgasms o Masters and Johnson research refute Freud’s o No difference between clitoral and vaginal  All female orgasms are same physiologically- consists of contractions of the orgasmic platform and muscles surrounding vagina o Clitoral stimulation is always involved in orgasm even in intercourse  The crura of clitoris runs deep and is stimulated by penile penetration, usually clitoris triggers the orgasm o Multiple orgasms possible in short period of time for women because no refractory period  If stimulation continues she can immediately be aroused and have another orgasm  More likely to result from hand-genital or mouth-genital stimulation than intercourse  Can have 5-20 during masturbation o Multiple orgasmic men exist but rare Other Models o Master and Johnson’s model ignores cognitive and subjective and focuses only on physiology o Desire and passion not part of the model o Subjective experience influenced by context and quality of the relationship + psychological factors o Research show 2 components: sensory dimension + cognitive-affective dimension o Model cannot be generalized to population Kaplan’s Triphasic Model o 3 independent phases= sexual desire + vasocongestion of genitals + muscular contractions of orgasm phase o first is psychological, latter 2 are physio o therefore adds cognitive part that master and Johnson lacked o physio stages controlled by different nervous systems o vasocongestion (erection and lubrication) parasympathetic of the autonomic nervous system o ejaculation/orgasm sympathetic o different anatomical structures o vasocongestion blood vessels o orgasm nuscles o vasocongestion and orgasm differ in susceptibility to age and drugs o refractory period lengthens with age o decrease in frequency of orgasms with age o capacity for erection unimpaired with age o ejaculation can be voluntary controlled but erection cannot o erection problems= impaired vasocongestion o rapid/delayed ejaculation= impaired orgasm response Intimacy Model o people in long term relationships motivated to engage in sex to enhance intimacy, closeness, and commitment o they begin sex in a neutral state but are receptive to sexual stimuli which will arouse them o emotional intimacysexual neutrality (receptive to) sexual stimuli sexual arousalsexual desire &arousal emotional and physical satisfactionemotional intimacy (the figure is a circle) The Dual Control Model o John Bancroft o 2 basic processes= excitation and inhibition o inhibition= adaptive process across species because excitation can be a distraction and disadvantageous o tendencies vary widely but extremes lead to either sexual dysfunction (lots of inhibition) or high risk behaviours (lots of excitation) o scales to measure excitation items o when I think of a very attractive person, I easily become aroused o when I am taking a shower I become easily aroused o inhibition items o I need my penis/clitoris to be continuosly touched to arousal o Putting on a condom causes me to lose my erection o Both processes have biological bases but cultural factors influence o Ex media tells what attractive women should look like and therefore influence what men find attractive o Sexual activity can be dangerous and sometime the environment isn’t conducive to reproduction o Excessive sex behaviour in men reduce fertility Emotion and Arousal o Researchers recruited mixed sex and same sex couples, kept diary of questionnaires asking about emotional and sexual behaviours o Over time showed positive emotions showed a strong positive association with reports of sexual arousal o Negative emotions were also correlated to arousal kuz anxiety and stress usually involve some sort of arousal Hormonal and Neural Bases of Sexual Behaviour The Brain, the Spinal Cord and Sex Spinal Reflexes o Important in erection and ejaculation o 3 parts o receptors sensory neurons that detect stimuli o transmitters in spinal cord or brain, receive message, interpret and send out response o effectors neurons/muscles that respond o ex: jerking your hand away when it touches something hot Mechanism of Erection o can be done through tactile stimulation, cognitive factors, or nearby regions like scrotum or thighs sends signal to erection centre in sacral part of spinal cord o parasympathetic division of autonomic tell muscles to relax allowing arteries to expand and fill with blood= erection o compression of outflow veins keep blood there o those who have had spinal cord severed in accident capable of erection by rubbing genitals although cant feel because neural signals cant be transmitted up the spinal cord Mechanism of Ejaculation o 2 ejaculation centers: higher in the spinal cord, lumbar portion o sympathetic and parasympathetic involved o response is muscular not vasocongestion o message sent to ejacualtion centremessage then sent via sympathetictriggers muscle contraction in internal organsejaculation o can be controlled voluntarily by controlling approach= shows importance of brain influences o 3 problems with ejaculation= rapid ejaculation + male orgasmic disorder + retrograde ejaculation o rapid ejaculation= most common o retrograde ejaculation= ejaculate empties into the bladder “dry orgasm” o can be caused by some illnesses, tranqs, prostate surgery, drugs for psychosis o 2 sphincters are desynchronized (internal closes off route to bladder, external opens during normal) o external one closes and internal one opens Mechanisms in Women o sensory input travels down doral nerve of clitoris pudendal nerve reflex centre in sacral spinal cord o neural circuits similar to men o clitoris and vagina gets sympathetic and parasympathetic nerve fibres o limbic system used in female/male arousal o female ejaculation= stroking grafenburg spot aka female prostate/skene’s gland o woman lying on her back best position for finding it o ducts open to urethra, stroking it sends urge to pee but done more=sexual pleasure o researchers argue it induces a uterine orgasm which is deeper contractions then clitoris orgasm o femal prostate makes prostate specific antign just like males Brain Control of Sexual Response o limbic system= border between central and outer brain, includes amygdala + hippocampus + cingulated gyrus, fornix, septum o Thalamus + pituitary + reticular formation aren’t part of if but closely connected o Male sex behaviour medial preoptic area of hypothalamus  given electrical stimulation in rats sexual behaviour o Genitals stroked paraventricular nucleus fires down spinal cord o Functional MRI tests show when shown erotic films the cingulated gyrus, thalamus and amygdala fire o Olfactory centres also play role Hormones and Sex Organizing vs. Activating Effects o Organizing fx= when hormones affect genital anatomy, cause change in organiationg of structures in the nervous or reproductive systems o Activating fx= when hormones activate certain behaviours o Ex injecting rat with testosterone= increased sex behaviour o Female pregnant guinea pigs were injected with testosterone o Female offspring couldn’t show female sexual behaviour testosterone organized hypothalamus in a male fashion o Born with masculine genitals o Given testosterone in adulthood activated male patterns of sexual behaviour o Opposite done to male rats o Shows we all have initial capacity to be either male or female o Human control is less hormonally controlled more brain controlled Testosterone and Sexual Desire o Effects libido, sexual desire in men o
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