 ~*~ Biological Transitions ~*~ Puberty-Pubertal development is the series of biological changes leading up2 reproductive capability /// average age of menstruation and spirmarch - around 12/12.5 /// .Chara of puberty-5stages /// .1) Rapid acceleration of growth- /// . weight/height increase height up 10’’ /// . “peak height velocity” boysgrow about 4 inches per year, girls grow about 3.5 inches per year /// accumulates 1/2 of one’s body weight /// . 2)develop sex chara /// Develop sex glands (gonads) – testes in males & ovaries in females /// . 3. Development ofsecondary sex chara /// .Bodily changes /// .Pubic hair (boys 10-15; girls 7-14) ///Facial & underarm hair, & oil & sweatproducing glands (two years after pubic hair) /// Breasts (girls 7-13) /// Penis growth & voice changes (boys 11-14.5) ///Testes & scrotal sac growth (boys 10-13.5) /// . 4. Changes in body composition /// Increases in muscle & fat /// Boysincrease in % muscle more than girls, girls increase in % fat more than boys /// Ratio muscle/fat boys: 3/1 /// Ratiomuscle/fat girls: 5/4 /// 5. Changes in circulatory & respiratory systems /// .Capacity of the heart & lungs increases/// .Magnitude of gains typically greater for males versus females /// WHY DOES PUBERTY HAPPEN? /// . Hormonesplay an important role /// Hormonal changes begin in the hypothalamus /// starts 2 release gonadotropin-releasinghormone (GnRH), which stimulates & regulates the production of hormones in other) /// TRIGGERS THEHYPOTHALAMUS 2 START THIS PROCESS? /// .starts once a threshold level of body fat is reached /// Fat cellsproduce a protein, leptin, which provides a signal 2 the hypothalamus – research more conclusive for females thanmales /// . DIFFERENCES IN PUBERTY /// . Timing of puberty influenced by environmental factors /// .Girls haveearlier puberty when they grow up w/ (a) relatively high levels of stress, (b) homes w/ highest level of conflict, and/or (c)stepfathers living in home /// .Why? Stress may trigger hormonal secretions, /// . IMPLICATIONS OF PUBERTY ///Reactions of others 2 changes /// .Treat adoles. dif /// .New types of attention /// .Increase in proportion of time spentw/ peers /// .Distance in parent-child relationships increases /// More negative interaction, less positive interaction, moreconflict /// .This is particularly the case w/ the mother in two-parent households (less change w/ pubertal developmentfound in single parent households) /// PUBERTY & MOOD /// .Mood rapidly fluctuates in veradolescence /// .Likely 2 bedue 2 frequent changes in activitie /// Puberty & Sleep /// .adoles.s typically go 2 bed later than before (around 1am) &also wake up later (around 10am) /// .New sleep pattern: delayed phase preference-don’t go along w/ school scheduals/// .at “best” just when school gets out! /// .Sleep deprivation in adoles.s linked 2 lower grades /// .EARLY VS. LATEPUBERTY /// . “timing” influences adoles.s’ experiences /// .Effects are dif. for boys & girls /// .outcomes is adoles.s’perceptions of whether they are early or late /// . BOYS /// .EARLY DEVELOPMENT /// .Associated w/ increasedpopularity, increased positive affect, feel strong & confident /// .Also at increased risk for prob behavior /// .LATEDEVELOPERS /// .Lower popularity /// .Some evidence of lower self esteem /// Higher levels of creativity, exploratorybehaviors, & social initiative /// .Implications for adjustment in adulthood? /// .EARLY DEVELOPERS – Moreresponsible, cooperative, self-controlled & sociable, but also more conforming, & humorless /// .LATE DEVELOPERS –more impulsive, more assertive, also more insightful, inventive, & creative /// . GIRLS /// .EARLY DEVELOPERS ///.Tend 2 be relatively popular /// .At risk for self-image probs, depression, anxiety, eating disorders, & panic attacks ///Important 2 note that this varies based on social-context (country of origin, race & SES, school climate) /// .At risk forprob behaviors & early sexual “onset” /// .At risk for sexual harassment from peers /// .LATE DEVELOPERS /// .Tend 2have a more favorable body image /// . IMPLICATIONS FOR EARLY PUBERTY INTO ADULTHOOD? /// .earlyadulthood, early developers still have higher levels of psychological & social probs /// . Early developers tend 2 havelower educational achievement /// . early developers tend 2 become parents earlier, & 2 marry earlier /// . WHY AREEARLY DEVELOPING GIRLS AT RISK /// . “Maturational deviance” hypothesis /// .Adoles. who are the most dif. fromthe majority of their peers, are at the most risk ///Early developing girls/Late developing boys/// “Developmentalreadiness” hypothesis/// Adoles. are most at risk when they have had the least time 2 mature cognitively &psychologically, prior 2 puberty /// .BODIES & PUBERTY /// . Thin is “in” in some cultures /// .For many girls, the ideal isclose 2 prepubescent appearance /// .girls at especially high risk are: /// .Girls already involved in prob behavior /// .Girlswho attend coeducational school versus an all-girls school /// . PHYSICAL W/ PUBERTY /// . time of great health & ofrelatively high risk! /// .low levels of chronic illnesses /// .High risk behavior=Driving, Eating, Substance use & Sexualbehavior /// . EATING DISOARDERS /// . Obesity /// Between 10 and 15% of adolescents are obese /// Up from 5%in 1980 /// factors that increase obesity =“Fast food nation”, 2/3 upper schools havevending machines, bad schoollunches!, not as much physical, more time with TV /// Anorexia/// .About .5% anorexic/// .90% female/// .characterizedby /// .Loss of at least 15% of weight, Cognitive distortion about body, Amenorrhea, About 10% die from this disorder Mostoften has onset during adolescence, Often co-occurs with other disorder /// Bulimia ///3% adolecs; About 90% females ///characterized by binging and purging; binge = up to10,000 calories at once ;Purge