Chapter 14: Adolescence: Biosocial Development

Why are many teenagers deficient in iron and calcium?

Because menstruation depletes iron, anemia is more common among adolescent girls. Boys everywhere may be iron-deficient if they engage in physical labor or intensive sports: muscles need iron for growth and strength. One reason for calcium deficiency is that milk drinking has declined significantly- some find milk difficult to digest, but other products- cheese or yogurt- could replace milk. Too many adolescents choose soda and chips.

What complications result from the sequence of growth (weight/height/muscles)?

Both weight and height increase before muscles and internal organs. Sports injuries are the most common school accidents, and they increase at puberty. One reason is that the height spurt precedes increases in bone mass, making adolescents particularly vulnerable to fractures.

How does the circadian rhythm affect adolescents?

Circadian rhythm is a day-night cycle of biological activity that occurs approximately every 24 hours. For most people, daylight awakens the brain, but at puberty, night may be more energizing, making some teens wide awake and hungry at midnight but half asleep, with no appetite or energy. Teens in adolescence risk suffering from the circadian sleep debt.

Why do adolescents experience sudden, intense emotions?

Cortisol levels rise at puberty, and that makes adolescents quicker to become angry or upset. Then those emotions, in turn, increase levels of various hormones. Bodies, brains and behavior all affect one another.

How are girls affected by early puberty?

Early maturing girls tend to have lower self-esteem, more depression, and poorer body image than do other girls. Additionally, some early-maturing girls have older boyfriends who are attracted to their womanly shape and girlish innocence. Early-maturing girls enter abusive relationships more often than other girls do.

Why are many adolescents unhappy with their appearance?

Few adolescents are happy with their bodies, partly because very few look like the bodies portrayed online and in magazines, movies and TV programs that are marketed to teenagers. Dissatisfaction with body image is not only depressing but can also be dangerous- many teenagers eat erratically and take drugs to change their bodies.

What body parts of a teenage boy or girl are the last to reach full growth?

Final and full development of breasts, testes, and pubic hair.

What are the sex differences in the growth spurt?

Genetic sex differences have a marked effect- in height, the average pubescent girl is about 2 years ahead of the average boy. Sex affects sequence as well- the female spurt occurs before menarche while the male spurt occurs after spermarche.

What is the pattern of growth in adolescent bodies?

Growth proceeds from the extremities to the core. Thus, fingers and toes lengthen before hands and feet, hands and feet before arms and legs, arms and legs before the torso. Growth is not always symmetrical; one foot, one breast or even one ear may grow later than the other.

How do hormones affect the physical and psychological aspects of puberty?

Hormones are body chemicals that regulate hunger, sleep, moods, stress, sexual desire, immunity, reproduction and many other bodily functions and processes, including puberty. Throughout adolescence, hormone levels correlate with physiological changes and self-reported developments.

How are boys affected by off-time puberty?

In the 21st century, early-maturing boys are more aggressive, law-breaking and alcohol- abusing than the average boy. The boys most likely to become depressed are those for whom puberty was both early and quick. Late puberty may also be difficult- slow developing boys tend to be more anxious, depressed, and afraid of sex.

What are the ethnic and cultural differences in the timing of puberty?

On average, African Americans reach puberty about 7 months before European or Hispanic Americans; Chinese Americans average several months later. The significance of all these changes is more gender than sex, more cultural than genetic.

What are the consequences of sleep deprivation?

Sleep deprivation and irregular sleep schedules increase several proven dangers, including insomnia, nightmares, mood disorders (depression, conduct disorder, anxiety), and falling asleep while driving. In addition, sleepy students do not learn as well as well-rested ones.

What are the first visible signs of puberty?

The first observable signs of puberty begin with nipple growth in girls and followed by a peak growth spurt, widening of the hips, and the first menstrual period, a full pubic-hair pattern and breast maturation. For boys, the usual sequence is growth of the testes, initial pubic hair growth, growth of the penis, appearance of facial hair, a peak growth spurt, deepening of the voice, and final pubic hair growth.