ch14-15

• Growth Spurt


  Rapid change in height and weight that marks onset of puberty
• Growth Spurt


  • Lasts 2-3 years
  • 45% skeletal growth
  • 37% total bone mass accumulated
• Height


  • Boys: 9 inches taller
  • Girls: 6-7 inches taller
  • All reach 98% of adult height by end
• Nutrition

  • Less sensitive to nutritional fluctuations
  • If has poor nutrition, delayed maturation
  • Limits reproductive success
  • Body needs 2x as much nutrition
• Prevents heart disease, cancer, osteoporosis
• Physical body underdeveloped, life-threatening consequences for mother and baby
• Puberty


  Biological developments from state of physical immaturity to biologically mature and capable of sexual production
• Gender differences in puberty


  • Boys: Exert more force/oz of muscle, exercise for longer periods, develop larger hearts and lungs, higher bp
  • Girls: Healthier, live longer, better tolerate long-term stress
• Cognitive functioning in adolescence

  1. Early: spurt in synapse production // synaptogenesis

  2. Late: synaptic pruning
• Primary Sex Characteristics


  • Reproductive organs/gonads consist of: Females - Egg producing ovaries, Males - Sperm-producing testes
  • Grow and become functional
  • Produce hormones: Estrogen & Progesterone, Testosterone
• Secondary Sex Characteristics


  Important in communicating individual's status as reproductively mature female/male
• Secondary Sex Characteristics in Males


  • Changes occur 3 years before boy reaches peak growth spurt
  • Growth of testes
  • Thickening/reddening of scrotal sac
  • Pubic hair
  • Penis begins 2-year period of growth
  • Halfway: ejaculation possible
  • Deepening of voice
• Secondary Sex Characteristics in Females

  • Breast Bud: small rise around nipples
  • Pubic hairs (just before growth spurt)
  • Breasts continue developing
  • Development of mammary glands: source of milk
  • Increase in adipose (fatty) tissue: gives adult shape
• Menarche


  • Girl's first menstrual period
  • Occurs late in puberty, about 18 months after growth spurt reached peak
  • Early menstruation tend to be irregular, often w/o ovulation
  • Regular ovulation begins 12-18 months after menarche
  • Uterus grows, vaginal lining thickens
  • Pelvic inlet (bony opening of birth canal) does not reach adult size until 18 years of age
• Semenarche


  • Boy's first ejaculation
  • Typically occurs spontaneously during sleep: nocturnal emission
  • After 1st year: boy's sperm less numerous, less fertile than later adolescent years
• Secular Trend


  • Pattern which average age of puberty in developed countries declines across decades
  • First seen as evidence of good health
  • Mid 1800s: Increased access to food, prenatal and child care, vaccines, medicine
  • Improve: Nutrition, Access to health care
  • Decline: "Overnutrition", Obesity and overweight, Declining physical activity
• Early Maturation


  • Occurrence of pubertal event (or set of events) before 3rd percentile of the normal range
  • Effect on Girls: Depressive/eating disorders, Anxiety, Poor self-esteem
  • Effect on Boys: More popular, Pleased by changing bodies
  • Effect on both: Delinquency, Substance abuse, Academic problems, Associate themselves with an older crowd; exposure to risky behaviors
• Late Maturation


  • Occurrence of pubertal event after the 97th percentile of the normal range
  • Genital growth takes longer than usual
• Formal Operations (Second-Order Operations)


  • Adolescents ability to systematically relate sets of relationships to each other (how everything connects)
  • Example: To make a profit, gas station owner must think of price of gas, kinds of customers to pass station, hours needed to stay open, cost of labor, supplies, rent, etc
  • Not universal, based on specific experiences
• Hypothetical-Deductive Reasoning


  • Involves ability to judge an argument entirely on basis of its logical form, regardless of whether argument is true
  • Example: 1st Premise: Elephants are bigger than mice. 2nd Premise: Dogs are bigger than mice, Conclusion: Therefore, elephants are bigger than dogs
  • Distinguish between truth and logic
• Morality of Justice (Carol Gilligan)


  • Morality emphasizes issues of rightness, fairness, and equality
  • "A person's right to live"
  • Boy-oriented
• Morality of Care


  • Morality that stresses relationships, compassion, and social obligations
  • Focuses on relationships, compassion, social obligations
  • Girl-oriented
• Emerging Adulthood


  • New stage of development facing individuals between ages of 18-25 in technologically advanced societies
  • Societies value innovation over tradition
  • Knowledge and values of parent generations are weakened, less relevant
  • Youth turn to each other, rather than parents
• Prefrontal Cortex


  • Directly behind forehead
  • Contribute to abilities involving controlling and regulating thoughts, feelings, behaviors
• Limbic System – "Emotion Brain"


  • Group of brain structures (amygdala, hippocampus, basal ganglia, hypothalamus)
  • Structure more associated with emotion than reasoning
• Hypothalamic-Pituitary-Gonadal (HPG) Axis


  • Responsible for regulating hormones that affect body's growth and functions
  • Circuit extends from brain to sex organs
  • Involved in puberty
  • Consists of: Hypothalamus, Pituitary glands, Sex glands
• Hypothalamus


  • Regulates hunger, thirst, sexual desire
  • Connected to endocrine system
  • Produces gonadotropin-releasing hormone (GnRH)
  • Stimulates pituitary gland to release hormones: gonadotropins
  • These travel to sex glands: produce estrogens (estradiol) and androgens testosterone) – sex hormones
• Endocrine System


  Network of hormone-secreting glands associated with changed in mood, metabolism, and growth
• Sex Hormones


  Estrogens and androgens that circulate bloodstream, activating hormone-perceiving receptors located in body
• Leptin


  • Hormone plays key role in appetite and metabolism
  • Increase body fat = increase leptin
  • When reach certain level, puberty hormones released
  • Evidence: children from well-off countries get puberty earlier than others
  • Thin, malnutrition = later puberty
• Kisspeptin


  • Plays key role in activation of HPG axis
  • Protein produced by cells in hypothalamus
  • Influenced by leptin and levels of estrogen and androgens
• Precocious Puberty


  • Condition involving activation of HPG axis before age of 8 in girls and 9 in boys
  • Associated with predispositions to disease: Cancer, diabetes, overweight
  • 5-10% more common in girls than boys
  • Higher rates in foreign adopted and migrant children in the U.S.
• Epistemic Development


  • Refers to changes in how individuals reason about the nature of knowledge
  • Children able to create their own beliefs on what is false or not
• Experience Sampling Method (ESM)

  • Tool by developmentalists, participants receive text messages containing Web link survey
  • Ask teens to describe: Positive and negative experiences, Who they are with, Physical location, How they feel
• Sensation-Seeking


  • Desire to participate in highly arousing activities
  • Encourages youth to leave their families to join peers for exploring new territory and selecting mates
  • Until frontal lobes matured, adolescents vulnerable to risk-taking, recklessness, emotional problems
• Friendship


  • Reciprocity: give-and-take of close relationships
  • Includes sharing emotions, interests, and activities
  • Commitment: loyalty and trust between friends
  • Equality: equal distribution of power among them
  • Significant developmental functions: Intimacy, Autonomy
• Gender Differences in Friendship

  • Girls: intense and intimate
  • Boys: less intimate and less trusting, less likely to share emotional details of lives
• Intimacy


  Sense of close connection between 2 individuals, resulting from shared feelings, thoughts, and activities
• Autonomy


  Ability to govern the self and assert one's own needs
• Homophobia


  • Fear of homosexuality
  • Prevents adolescent males from demonstrating/admitting to strong feelings of intimacy towards male friends
  • Expressions: Name-calling, More common in boys than girls