Chapter 11: Physical and Cognitive Development in Adolescence
PHYSICAL DEVELOPMENT
1. Adolescence- the transition between childhood and adulthood
2. Puberty- a flood of biological events leading to an adult-sized body and sexual maturity. The physical transition to adulthood.
A. Hormonal Changes
Hormonal changes gradually begin by age 8-9
Increase of GH and thyroxin
Sexual maturation controlled by sex hormones (estrogen, androgen)
Testes release large amounts of the androgen, testosterone muscle growth, body and facial hair
Ovaries release estrogen breast, uterus, and vagina maturation, broadening of the hips, fat accumulate, and regulation of menstrual cycle
In both sexes estrogens increase GH secretions growth spurt, and gain in bone density
Adrenal androgens, released from the adrenal gland on top of each kidney female growth spurts, and stimulate growth of underarm and pubic hair
A. Body Growth
Growth spurt- the first sign of puberty, the rapid gain in height and weight
Growth spurt occurs in girls by age 10
Growth spurt occurs in boys by age 12.5
Growth is complete for most girls by age 16
Growth is complete for most boys by age 17.5
Adolescents add 10-11 inches in height and 50-75 pounds
A. Motor Development and Physical Activity
Boys show a dramatic increase in strength, speed, and endurance
Peer admiration and self-esteem are related to athletic competence in boys
A. Sexual Maturation
Primary sexual characteristics-
Female
Ovaries
Uterus
Fallopian tube
Vagina
Male
Testes
Scrotum
Prostate gland
Seminal vesicle
Penis
Secondary sexual characteristics-
Female
Breast
Pubic hair
Underarm hair
Change in voice
Acne
Broadening of hips/pelvis
Muscular dev.
Male
Pubic hair
Underarm hair
Muscular dev.
Facial hair
Change in voice
Acne
Broadening of shoulders

Menarche- first menstruation occurs in girls around age 12-13
Spermarche- first ejaculation occurs in boys around age 13.5
A. Individual Differences in Pubertal Growth
Secular trend- a change from one generation to the next in an aspect of development, such as body size or pubertal timing.
Heredity, nutrition, exercise, and poverty all affect the timing of puberty
A. Brain Development
Growth and myelination of neural fibers accelerate and strengthen the 2 cerebral hemispheres through the corpus callosum
Adolescent brain supports processing speed, attention, memory, planning, integrate info, and self-regulation
Neurons become more responsible to excitatory neurotransmitters during puberty (stressful events, peer pressure, and pleasurable stimuli)
The brains regulation of sleep results in adolescents wanting to go to bed much later
1. The Psychological Impact of Pubertal Events
A. Reactions to Pubertal Changes
Girls and boys are uninformed and often have no advance for puberty changes
Shocking and sometimes disturbing experience
Girls tend to tell a friend about getting their period, unlike boys who tend to not tell anyone
A. Pubertal Change, Emotion, and Social Behavior
Higher peaks in emotional experiences
Greater moodiness
Adolescents want more privacy
Resist spending time with family Become more argumentative with parents (curfew, dating, driving)
A. Pubertal Timing
Early maturing boys are relaxed, independent, self-confident, physically attractive, looked up to as a leader
Later maturing boys are anxious, overly talkative, attention seeking, awkward
Early maturing girls are unpopular, withdrawn, lack self-confidence, involve in deviant behavior (sex, drugs, alcohol)
Late maturing girls are physically attractive, sociable, leaders
Body image- conception of and attitude toward their physical appearance
1. Health Issues
A. Nutritional Needs
Rise in food intake
Boys require 2,700 calories a day, plus more protein
Girls require 2,200 calories a day
Unhealthy food choices (fast food, skipping breakfast)
A. Eating Disorders
Anorexia nervosa- tragic eating disturbance in which young