Biology Ch.5-6 Biol360
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CH. 5 BOOK NOTES • WHR. Waist-to-hip Ratio: the ratio of the circumference of the body at the waist to the circumference at the hip • COOLIDGE EFFECT: the revival of sexual arousal caused by the presence of a novel partner • HABITUATION: a psychological or physiological process that reduces a person’s response to a stimulus or drug after repeated or prolonged exposure • ASEXUAL: Describes a person who never experiences sexual attraction • FANTASY: an imagined experience sexual or otherwise • HYPOGONADAL: producing insufficient levels of sex hormones • APHRODISIAC: a substance believed to improve sexual performance, enhance sexual pleasure, or stimulate desire or love. Named for the greek goddess of love. aphrodite • CLASSICAL (OR PAVLOVIAN CONDITIONING) a form of behavioral learning in which a novel stimulus is tied to a preexisting reflex • SEXUAL RESPONSE CYCLE: the sequence of physiological processes that accompany sexual behavior • EXCITEMENT PHASE: the beginning phase of sexual response cycle • VASOCONGESTION: tissue swelling caused by increased filling of local blood vessels • PLATEAU PHASE: the phase of sexual sexual response cycle during which arousal is maintained at a high level • ORGASMIC PLATFORM: the outer portion of the vagina and surrounding tissues, which thickens and tenses during sexual arousal • MYOTONIA: a general increase in muscle tension • ORGASM: the intense, pleasurable sensations at sexual climax, and the physiological processes that accompany them • NUCLEUS ACCUMBENS: a nucleus within the basal ganglia that is part of the brain’s reward system • OXYTOCIN: the hormone secreted by the pituitary gland that stimulates uterine contractions and the secretion of milk • RESOLUTION PHASE: the phase of sexual response cycle during which physiological arousal subsides • MULTIPLE ORGASMS: two or more orgasms, between which the person descends only to the plateau level of arousal • SERIAL ORGASMS: two or more orgasms with no more than a few seconds between them • REFRACTORY PERIOD: in males, a period of reduced or absent sexual arousability after orgasm • SEXUAL ATTRACTION is a response to another person that is influenced by objective attributes of that person, as well as by both durable and varying characteristics of the person experiencing the attraction • The “masculinity” and “femininity” of faces is an important part of their attractiveness • In women, most people find very feminine faces the most attractive • Women’s judgement of the attractiveness of male face vary around their menstrual cycle • Another attribute that increases a person’s “attractiveness” is facial and bodily symmetry • One reason we may find symmetry attractive is because it indicates that a person had a healthy physical development • One important factor influencing the attractiveness of bodies is the body mass index (BMI) • For cultural reasons, lower BMI’S are preferred in western cultures than in some non-western cultures • Youthful appearance- another cue to fertility- is an important criterion of physical attractiveness in women but less so in men • Attractiveness is strongly enhanced by general “likability” traits such as trustworthiness, warmth, and a sense of humor • People are given the opportunity to select partners from a large group, however they don’t generally choose the partners who correspond most closely to their stated preferences • This suggests that some aspects of attraction operate below the level of conscious thought • Other factors modulating sexual attraction include familiarity in women, the phase of the menstrual cycle. • Some individuals are asexual: they never experience sexual attraction. They might not engage in sexual relationships, or they might do simply to satisfy their partners • Sexual arousal may be triggered internally or by external factors • Internal processes include erotic dreams and sexual fantasies • Fantasies are a healthy part of most people’s sex lives • Testosterone plays an important role in conferring the capacity for sexual arousal in males, especially at puberty • Testosterone does not play a minute-by-minute role in sexual arousal, • However both testosterone and estrogens may contribute to sexual arousability in women; • Testosterone is probably the more important of the two • Classical conditioning may increase the sexual arousal that individuals learn to associate with people, body parts, and other things that have been linked with sex in the past • The sexual response cycle has 4 phases: EXCITEMENT, PLATEAU, ORGASM, RESOLUTION • The subjective experience of orgasm is similar in women and men. • Many women but few men experience multiple orgasms in a single cycle • Sometimes a response cycle does not include orgasm • A cycle without orgasm may be perceived as sexually satisfying or it may leave the person dissatisfied and in discomfort from vascongestion that is slow to resolve • After orgasm, men but not women experience a refractory period during which they cannot enter a new cycle • The length of the refractory period increases with age but can be shortened by situational factors such as exposure to a novel partner CH. 6 BOOK NOTES • MASTERBATION: sexual self stimulation. Sometimes also used to refer to manual stimulation of another person’s genitalia • AUTOEROTIC: providing sexual stimulation to oneself or being aroused sexually by oneself • NECKING: kissing or caressing of the head and neck • PETTING: Sexually touching the partner’s body (often taken to exclude the breasts or genitalia ) • HEAVY PETTING: Sexually touching the partners genitalia or breasts • MUTUAL MASTERBATION: Reciprocal simultaneous manual stimulation of a partners genitalia • FONDLING: any kind of sexual touching of the partner’s body • OUTERCOURSE: sexual activities other can coitus, promoted as means for preventing unwanted pregnancy and reducing the risk of STD transmission • TRIBADISM: sexual behavior between two women, who lie front to front and stimulate each other’s vulvas with thrusting motions • FOREPLAY: Sexual behavior engaged in during the early part of a sexual encounter, with the aim of increasing sexual arousal • AFTERPLAY: sexual behavior engaged in after coitus or orgasm, or at the end of a sexual encounter • FELLATIO: sexual contact between the mouth of one person and the penis of another • CUNNILINGUS: sexual contact between the tongue or mouth of one person and the vulva of another • ANILINGUS: sexual contact between the mouth or tongue of one person and the anus of another • ANAL SEX: penetration of the anus by the penis, or any sexual behavior involving the anus • SPHINCTER: a circular muscle around a tube or orifice whose contraction closes the orifice • RECTUM: the final, straight portion of the large bowel, it connects the exterior via the anus • PREMATURE EJACULATION: ejaculation before the man wishes, often immediately on commencement of coitus. Also called rapid ejaculation • VIBRATOR: an electrically powered vibrating device used to provide sexual stimulation • DILDO: a sex toy, often shaped like a penis, used to penetrate the vagina or anus • SEX PLAY: a variety of playful activities that add pleasure to sexual interactions • SEMINAL NATURE: the belief that fetuses require repeated infusions of semen to grow • QUADRIPLEGIA: paralysis affecting almost the entire body below the neck • PARAPLEGIA: paralysis affecting the lower half of the body • HISTORICALLY attitudes towards masturbation or autoerotic behavior have been quite negative • These attitudes derive from moral teachings, from the notion that masturbation is unhealthy and a form of sense that people who masturbate are those who cant find a sex partner • According to the NHSLS about half of US adults masturbate at least once per year • Factors associated with higher rates of masturbation include a younger age and a higher educational level • Factors associated with lower rates include having a regular sex partner, being more religious, and being African American • Gay people masturbate more than heterosexuals and derive more enjoyment from it • Masturbation does not seem to be simply a substitute for sex with partners • Men tend to use a single technique for masturbation-direct manual stroking of the penis- • Whereas women use a greater variety of techniques, such as manual stimulation of the clitoris, labia, or vagina, or rubbing of the vulva against objects • Men experience orgasm during masturbation more frequently than do women • Kissing in an important form of sexual expression in the US where it often has strong romantic significance, but is not practiced in all human cultures • Sexual touching includes a variety of behaviors short of penetrative sex. • It may be a prelude to penetrative sexual interaction (foreplay) • Or it may form the entire sexual encounter, especially among adolescents • Oral sex means contact between the mouth and the penis (fellatio), the vulve (cunnilingus) or the anus (anilingus) • Oral sex has become increasingly popular among younger people in the US and BRITAIN • Like many noncoital sexual behaviors, it is more common among well-educated people • About half of US, men but fewer women, find fellatio very appealing • Men and women enjoy cunnilingus about equally • Approximately one third of the US population find it appealing • Oral sex may be performed mutually in a head to genital arrangement; this position is called sixty nine, or soixante neuf • Most adult heterosexual couples engage in coitus as the culmination of a sexual encounter • The most popular traditional position for coitus in the US is missionary • Which requires the man to do most of the pelvic thrusting • The 1970s encouraged the exploration of other positions, such as the women- above position and rear-entry coitus • Each position may have particular advantages and disadvantages for certain couples or in certain situations • ANAL SEX (penetration of the anus by the penis) is practiced in both male-male and female-male encounters. • Anal sex can be performed in a variety of positions and need not damage the anus or rectum • Some couples like to make coitus almost the entirety of a sexual encounter, while others include much foreplay and afterplay, or even dispense with coitus altogether • Women generally take longer to orgasm than men • So men might have to learn to postpone their own orgasm in heterosexual encounters if the man and women wish to experience orgasm at close to the same time • Vibrators are electrically powered devices that deliver erotically arousing vibratory stimulation • Men or women may use them, but they are particularly associated with use for masturbation by women and to help women reach orgasm in partnered sex • Dildos are unpowered, sometimes penis shaped objects used for vaginal or anal penetration, in either partnered or solo sex • Different cultures vary greatly in the openness with which they discuss sexual behavior • One classic how to manual on sex behavior is the Kama Sutra (india 5 century or earlier ) • This book demonstrates that explicit discussion of sex is not the sole prerogative of modern western society • Contemporary india, however, has attitudes towards sex that are less positive than those described in the KAMA SUTRA • Among the AKA, an African hunter-gatherer people, couples have sex at high frequencies throughout their fertile years. • This practice is connected with the belief that multiple acts of coitus are required to nurture a fetus • Most intellectually disabled people experience the same sexual feelings and desires as everyone else. They have a right to make informed choices about sexual behavior if they are capable of doing so • Facilitating the exercise of this right must be balanced against the need to protect intellectually disabled people from sexual exploitation • With appropriate education, many intellectually disabled people can enjoy active sex lives, and some become parents and raise children • Spinal cord injuries can cause near-complete loss of movement and sensation in the body below the neck (quadriplegia) or in the lower half of the body (paraplegia) although conscious sensations from the genitalia are often lost, reflex penile erection and vaginal lubrication and engorgement may be preserved • Depending on the level of injury and whether the spinal cord has been completely severed • Most people with spinal cord injuries can engage in coitus if they desire it • And women with spinal cord injuries can sustain pregnancy and deliver a baby vaginally • Some disabilities interfere with sexual behavior by limiting movements or making movements painful • Arthritis is the leading culprit in this respect, with 15% of th e US population affected • Nevertheless people with arthritis can usually engage in pleasurable and rewarding sex by advance preparation and by choosing positions for sex that put the least stress on affected joints LECTURE NOTES AROUSAL AND RESPONSE Sexual AROUSAL follows a RESPONSE CYCLE The best-known model was developed by Masters and Johnson and is divided into 4 phases of physiological changes EXCITEMENT o General Changes in males and females: o VASOCONGESTION: accumulation of blood in a region, in this case the genital region o SEX FLUSH: not seen in everyone but in some individuals, sex flush appears as a rash from the upper abdomen to the entire chest. It is more commonly seen in females but does occur in men as well o INCREASE IN HEART RATE AND BREATHING during the excitement phase o NIPPLE ERECTION: caused by the muscles around the nipple contracting SPECIFIC changes in MALE The vasocongestion of the penis resulting in an erection There are 3 cylinders of erectile tissue in the penis 2 capora cavernosa which fills with blood before the single corpus spongiosum The scrotum will move closer towards the body as the cremaster muscles contract • SPECIFIC changes in FEMALES • Increase in vaginal lubrication • VASOCONGESTIONS of the female is the swelling of the clitoris and labia minora (causing them to spread) allowing more access to the introitus due to the increase of the blood to the region • Upper two thirds of vagina opens up in a process called ballooning • In an unaroused state, the walls of the vagina lie against each other • This separation will prepare the vagina for penetration • The uterus pulls up and elevates in a process known as tenting which also prepares the body for penetration PLATEAU o GENERAL changes for men and female o Arousal reaches its peak but orgasm has not begun o VASOCONGESTION reaches its peak which has led to the swelling of the breasts, clitoral and penal erections, and in some individuals the sex flush o A general increase in muscle tension called myotonia occurs throughout the body o All of these changes are linked to elevated heart rate and blood pressure SPECIFIC changes in MALES Penis completely erect And the glans swell due to the vasocongestion that has trapped blood in the region The testes are fully swollen and elevated At this phase the bulbourethral gland may release a small amount of fluid known as precum This fluid helps prepare the urethra for the passage of semen as it will exit the body • SPECIFIC changes in FEMALES • Orgasmic platform will form, and it is when there is a tightening of the outer third potion of the vagina • This tightening can be felt during penetration by the male in a phenomenon reffered to as penile containment • Elevation of the clitoris. The glands of the clitoris will retreat behind the clitoral hood ORGASM o GENERAL changes o Sharp increase in pulse rate, blood pressure, and breathing rate. They will reach peak levels o Brief sequence of muscle contractions of the genitals and surrounding areas o During this time there is changes in the activity of the persons brain o The cognitive centers of the brain will decrease in their activity while the activity in the pleasure centers increases o Some people can experience multiple orgasms o When this occurs the individual goes back to the plateau phase and achieves climax again. This is more common in women than men SPECIFIC changes in MALES 2 key events : emission and expulsion EMISSION (“ejaculatory inevitability”)- there is a contraction of prostate, seminal vesicles and vas deferens to release their perspective fluid contributions to the semen Once this contraction occurs, it is said that the male has reached the point referred to as ejaculatory inevitability (the point of no return for the male) EXPULSION: the release of the semenfrom the males body Contractions of urethra and pelvic floor muscles Release of semen EJACULATION PROBLEMS Premature ejaculation occurs when the individual ejaculates before the desired time Approaches to help individuals with this would be various drugs and a stop start method that increases a persons sexual ability to stay in coitus \ Retrograde ejaculation is when the semen moves up the urethra and into the bladder instead of exiting the body. This is not harmful or painful but it may startling to experience an orgasm with little to no semen released This will have an effect on fertility because the sperm is not being delivered to the egg • SPECIFIC changes in FEMALES • Contractions of orgasmic platform and uterus • Main feeling begins around the clitoris and then spreads outward through the whole pelvis • Some women experience a release of fluid that has been linked to the paraurethral gland • This does not occur in everyone but the amount of liquid released is relatively minimal RESOLUTION o GENERAL changes o Sexual arousal usually subsides at this phase o VASOCONSTRICTION when the blood dissipates from the region resulting with the body returning to its unaroused state o Most men have a REFRACTORY PERIOD during which further sexual stimulation does not lead to arousal o It can be absolute which means they cannot be stimulated by any means o Or it can be a relative refractory period meaning they can only be stimulated with stronger than usual stimuli o Women: no refractory period William Masters and Virginia Johnson’s study was based on Observing over 10,000 sexual cycles with 382 women and 312 men Their observations led to the creation of a model of the sexual response cycle CRITICISMS of Masters and Johnson’s Their model focused on the physiological aspects of the response It does not address the psychological components. Ignored thoughts and emotions They also excluded anyone whose pattern of sexual response did not include orgasm therefore limiting the info they were able to collect SEXUAL AROUSAL: COGNITIVE-PHYSIOLOGICAL MODELS By Helen Singer Kaplan Her model identifies 3 relatively independent phases: SEXUAL DESIRE: Unlike masters and johnson’s cycle, Kaplan incorporated the idea that an individuals sexual desire were very important for arousal and would lead to the physiological changes VASOCONGESTION. Similar to the excitement and plateau phases ORGASM: reflex muscular contractions of the orgasm phase THE NERVOUS SYSTEM: 2 PARTS Peripheral and Central CNS CENTRAL NERVOUS SYSTEM: includes the brain and spinal cord. They are involved in the body’s reflexes , like an erection PERIPHERAL NERVOUS SYSTEM: Divided into the sensory and motor division SENSORY: responsible for Detecting changes to the external and internal environments of the individual Receptors to detect stimulation These changes are detected by the nerve endings throughout the body MOTOR: allows for the voluntary or involuntary responses Effectors that respond (voluntarily or involuntarily) to stimulation Voluntary responses are carried out with the somatic nervous system that controls things like arm or leg movements Involuntary is carried out by the autonomic nervous system, which are responses you cant control like the dialation of pupils The responses are carried out by effector nerve cells which are distributed throughout the body The difference between the effectors and the receptors is the direction of information RECEPTORS send messages to the central nervous system CNS While the EFFECTORS carry them away THE CENTRAL NERVOUS SYSTEM and the PERIPHERAL NERVOUS SYSTEM work together to coordinate your body’s responses The SENSORY division of the PERIPHERAL NERVOUS SYSTEM detects the messages and sends them to the CENTRAL NERVOUS SYSTEM Receptors receive the stimulation sends message to CNS which interprets them and triggers a response creates response to stimulation AUTONOMIC RESPONSES is divided to the PARASYMPATHEIC DIVISION (rest and digest”) and the SYMPATHETIC DIVISION (“fight or flight”) preparesyour body to respond with fret includes: DILATION OF PUPILS which is good for keen vision increase of epinephrine and norepinephrine which helps with breathing accelerated heart rate which makes you have a better physical response increases the release of glucose for energy for your muscles at the same time the SYMPATHETIC RESPONSES suppress physiological functions that would be deemed no essential in a time of crisis such as digestion and sexual arousal it also causes the relaxation of the bladder which is why it is easy to pee during a threat PARASYMPATHETIC these responses include digestions and for one to become SEXUALLY STIMULATED They are involved in returning the body to its normal state after a threat or arousal ERECTION is controlled by PARASYMPATHETIC RESPONSE in the AUTONOMIC NERVOUS SYSTEM 2 DIFFERENT triggers to an erection The direct stimulation of the region or other stimuli such as scent or a visual image Direct stimulation of the genitals will send a message to the spinal flex center located in the lower portion of the spinal cord and can interpret stimulation and cause an erection This can occur without sending messages back to the brain for interpretation Other stimuli besides touch would be interpreted by the brain causing the message to be sent to the CNS that would cause an erection ORGASMS are controlled by SYMPATHETIC AND PARASYMPATHETIC RESPONSE which is why some people describe an orgasm as having a loss of control There is an overload in the nervous system in that particular moment WHAT ROLES HORMONES PLAY TESTOSTERONE: Levels affect the ability to become aroused in males and females However it is not been shown to affect desire or performance Higher levels do not increase interest in sex but their ability to respond to sexual stimuli ESTROGEN has indirect affects on the sexual response cycle Estrogen levels are linked to the production of the of lubrication from the vaginal mucosa While estrogen levels drop, low levels cause vaginal dryness (menopause) and can cause discomfort with friction but commercial lubricants work OXYTOCIN is produced by the pituitary gland and causes the contraction of smooth muscles such as the myometrium of the uterus There are several scenarios that would lead to an increase in the levels of oxytocin ORGASM In males and females theres a surge of oxytocin in orgasm, Research has shown higher levels linked to greater perceived orgasm intensity CHILDBIRTH Positive feedback during labor increase the output of oxytocin which increases the contraction of the uterus Those contractions cause more oxytocin to be released and the intensification of labor BREASTFEEDING Oxytocin is known as the cuddle hormone Promotes nurturing and affectionate behavior PROLACTIN surges after orgasm in both males and females This surge counteracts the effects of dopamine and results in the reduction of desire It is thought that the spike in prolactin is responsible for the refractory period that males experience during the resolution phase Reduces desire