Steinberg Chapter 1 Flashcards
What is puberty?
Puberty is a flood of biological events leading to an adult size body and sexual maturity, thus enabling young people to fulfill their biological destiny specifically sexual reproduction and survival of the species. It also more broadly encompasses all the physical changes that occur in adolescents as they pass from childhood into adulthood (Dorn & Biro, 2011).
If no new hormones are produced at puberty then what’s changing hormonally?
The levels of some hormones (that have been present since before birth) increase, whereas others decrease.
Describe the disproportionate production of different types of gender-related hormones during adolescence?
Males: androgens > estrogens
Females: estrogens > androgens
During adolescence the average male produces more androgens compared to estrogens. The opposite is true of females who produce more estrogens compared to androgens (Susman & Dorn, 2009).
What is the name of the mechanism responsible for maintaining certain levels of androgens and estrogens?
When these hormonal levels fall below the HPG axis set points, what is responsible for disinhibiting the pituitary?
This disinhibition permits the pituitary to stimulate the release of sex hormones by the gonads, and other puberty-related hormones by the adrenal gland. When hormone levels reach the set point, the hypothalamus responds by inhibiting its stimulation of the pituitary gland. Your brain is constantly monitoring a variety of signals and adjusting your hormonal set points in response.
HPG axis
hypothalamus
What are the 3 chief physical manifestations of puberty? (PSR)
- Development of primary sex characteristics (gonads, hormonal changes) ultimately enabling reproduction
- Development of secondary sex characteristics (genitals, breasts, pubic, facial, and body hair)
- Rapid acceleration of growth, specifically height and weight.
Puberty is the result of the development of what 2 systems?
Clint Eastwood
Central nervous system (Clint) Endocrine system (Eastwood)
When does puberty begin?
Puberty may appear to come on suddenly, judging from its external signs, but in fact it is part of a gradual process that begins at conception.
What is the function of the endocrine system during puberty?
It produces, circulates, and regulates levels of hormones
What are hormones?
Highly specialized substances secreted by one or more endocrine glands and then enter the bloodstream and travel throughout the body.
What are glands?
Organs that stimulate particular parts of the body to respond in specific ways to particular hormones.
What are gonadotropin-releasing hormone (GnRH) neurons?
Specialized neurons that are activated by certain pubertal hormones.
Where does the endocrine system receive its instructions from to increase or decrease circulating levels of particular hormones?
The central nervous system
In what way is the endocrine system like a thermostat?
Hormonal levels are “set” at a certain point, which may differ depending on the stage of development. When a particular hormonal level in your body dips below the endocrine system’s set point for that hormone, secretion of the hormone increases; when the level reaches the set point, secretion temporarily stops. Hormone can be adjusted up or down, depending on environmental or internal bodily conditions.
At the onset of puberty, a feedback loop ensues. What are the 3 components of this feedback loop?
Hypothalamus
Pituitary gland
Gonads
What are gonads?
Glands that release sex hormones: in males, the testes; in females, the ovaries.
What is the pituitary gland?
Responsible for regulating levels of hormones in the body.
What is the hypothalamus?
Part of the brain that controls the pituitary gland, and where there is a concentration of GnRH neurons. When the hypothalamus malfunctions puberty is delayed. Seeing a reproductive endocrinologist is recommended.
It is inaccurate to say that adolescence is an inherently stressful time. But what is true about stress during adolescence?
Adolescents experience a heightened vulnerability to stress.
What is one reason adolescence is a period of great vulnerability for the onset of many serious mental disorders?
The hormonal changes of puberty make adolescents more responsive to stress (Monahan, Guyer, Silk, Fitzwater, & Steinberg, 2016; Romeo, 2013; Stroud et al., 2009; Trépanier et al., 2013; Worthman, 2011). This leads to excessive secretion of the stress hormone cortisol, a substance that at high and chronic levels can cause brain cells to die (Carrion & Wong, 2012; Gunnar, Wewerka, Frenn, Long, & Griggs, 2009).
Hormonal changes during puberty—> more responsive to stress—> excessive secretion of cortisol —> chronic levels of cortisol = possible brain damages
What is adrenarche?
The maturation of the adrenal gland. More specifically, the adrenal gland releases a slightly higher level of sex hormones between 6 and 8. By the age of 10 levels of those sex hormones (adrenal androgens) have increased 10 fold, evidenced by most people report having their first sexual attraction at the magical age of 10 before they went through puberty. (From Berk and Steinberg Texts)
What triggers puberty?
GENETIC FACTORS
a) the HPG axis reawakens (the first awakening occurs prenatally) signaling to the body it’s ready for puberty.
b) a “puberty alarm” is set very early in life by information coded in the genes. In other words, the age at which someone goes through puberty is largely inherited. Genetics determine the upper and lower age limits (as opposed to a fixed absolute age).
c) an increase in the brain chemical kisspeptin. Leptin stimulates its production and melatonin suppresses it.
d) Quantity of fat cells (leptin) (obese children will go through puberty on the early side of their inherited propensity)
e) levels of melatonin. Low levels means kisspeptin is NOT being suppressed.
ENVIRONMENTAL FACTORS (some of the reawakening of the HPG axis at puberty is due to multiple environmental signals)
a) availability of sexually mature mating partners in the environment
b) sufficiency of nutritional resources to support a pregnancy
c) physically maturity and sufficient health to begin reproducing
d) frequency of exposure to light (children who live close to the equator
are more likely to go through puberty on the early side of their inherited propensity)
e. the environment determines the timing and rate within the upper and lower age limits that were genetically predetermined.
By far the 3 most important environmental influences on pubertal maturation are what?
What 5 factors predict pubertal timing from an environment perspective?
Nutrition Health The overall physical well-being of the individual from conception through preadolescence 1) Height 2)Weight 3) history of protein and/or caloric deficiency 4) Chronic illness 5) Excessive exercise
How do researchers know that the timing and tempo of pubertal timing is largely inherited, involving both genetic and chromosomal components?
Researchers compare identical twins and individuals who are not genetically identical. Also, a specific region on chromosome 6 has been identified as one of the markers for pubertal timing in both boys and girls (Bogin, 2011)
Why do obese children tend to start puberty early?
Obese children have more body fat and therefore produce a lot more leptin, which stimulates kisspeptin production
Why do children who live closer to the equator tend to start puberty early?
Children who live near the equator are exposed to relatively more sunlight each year, and they have lower melatonin levels as a result, so their kisspeptin production is not suppressed as much as it is among children who live closer to the poles. Exposure to artificial light, especially the kind of light emitted from electronic gadgets, can also suppress melatonin levels and hasten puberty (Greenspan & Deardorff, 2014).
Are changes in behavior at puberty the result of changes in hormones at that time?
Yes and No
1) increased levels of hormones during puberty affect behavior during puberty.
2) prenatal hormones set in
motion long before puberty affect behavior during puberty.
3) the interaction between increased hormone levels and prenatal hormones affect behavior during puberty.
Long before adolescence—in fact, before birth—hormones organize the brain in ways that may not be manifested in behavior until childhood or even adolescence (Sisk & Foster, 2004). This sex difference in prenatal brain organization predetermines certain patterns of behavior, many of which may not actually appear until much later (Collaer & Hines, 1995). Sex differences in aggression, for example, likely result from the impact of prenatal hormones, rather than from hormonal changes at puberty. In sum, exposure to certain hormones before birth may set a sort of alarm clock that does not go off until adolescence.
How do increases in hormonal levels during puberty affect brain development?
It likely increases adolescents’ emotional arousal and desire for highly rewarding, exciting activities, which may make some teenagers more prone to emotional and behavioral problems (Castellanos-Ryan, Parent, Vitaro, Tremblay, & Séguin, 2013; Forbes & Dahl, 2010; LeMoult, Colich, Sherdell, Hamilton, & Gotlib, 2015; Op de Macks et al., 2011; Speilberg et al., 2015.)
What 3 hormones are simultaneous released that stimulates rapid acceleration in height and weight? (TAG)
thyroid hormones
androgens
growth hormones
Define adolescent growth spurt? During the AGS,
what is it call when adolescents are growing most rapidly?
The rapid acceleration of growth, particularly height and weight.
peak height velocity
During peak height velocity, how many inches in one year does a boy and girl grow?
During this time how much weight can a boy and girl gain in a single year?
Approximately how many inches do boys and girls grow over the course of adolescence?
Approximately how many pounds do boys and girls gain over the course of adolescence?
4 inches 3.5 inches Boy: 26 lbs Girl: 20 10 to 11 inches in height 50 to 75 pounds
What is one marker signifying the conclusion of puberty?
epiphysis or the closing of the ends of the long bones in the body, which terminates growth in height.
Puberty is a time of significant increase in weight. What percent of one’s adult body weight is gained during adolescence (Susman & Dorn, 2009.)
Nearly half
What is the sequence in body growth that might make adolescents look awkward or gawky?
Extremities—the head, hands, and feet—are the first to accelerate in growth. Accelerated growth occurs next in the arms and legs, followed by torso and shoulder growth.
Before puberty, there are relatively few sex differences in what 2 physical features?
By the end of adolescence what is the muscle-to-fat ratio of boys and girls?
Muscle
Body fat
3:1
5:4
We know that puberty contributes to sex differences in physical performance. But what is not commonly known is that environmental factors play a key role too. Describe 3 environmental factors that contribute to sex differences in physical performance?
1) Strong social pressures on girls to curtail “masculine” activities including some forms of exercise
2) girls are more likely than boys to markedly reduce their physical activity in preadolescence
3) adolescent girls’ diets, especially those of Black girls, are generally less adequate nutritionally than the diets of boys, particularly in important minerals like iron (Johnson, Johnson, Wang, Smiciklas-Wright, & Guthrie, 1994.)
What is the relationship between puberty and dieting among adolescent girls?
Puberty leads to unexpected weight gain misattributed to other factors. This natural weight gain prompts girls to start dieting unnecessarily even when their weight falls in the normal range for their height.
Among adolescent girls, who is the most susceptible to feelings of dissatisfaction with their bodies?
Girls who mature early and begin dating early (Smolak et al., 1993).
What factors tend to make girls more vulnerable to feelings of body dissatisfaction?
1) High frequency of conversation with friends about body image.
2) Girls who are teased about their weight
3) Girls who are pressured to be thin a
4) Comparing themselves with their friends
5) Frequency of exposure to media portrayals of thinness
Webb & Zimmer-Gembeck, 2014).
Ferguson, Muñoz, Garza, & Galdino, 2014
What 2 factors characterize body satisfaction among boys?
Degree of muscularity
Less affected by comparisons with peers
What are the ethnic and cross-cultural differences in body satisfaction among adolescent girls?
1) In many parts of the world, including North and South America, Europe, and Asia, there is strong pressure on girls to be thin (Jones & Smolak, 2011).
2) Black adolescents seem less vulnerable to these feelings of body dissatisfaction (Ali, Rizzo, & Heiland, 2013; Jung & Forbes, 2013; Nishina, Ammon, Bellmore, & Graham, 2006), and consequently they are less likely to diet. Why? Because of the ethnic differences in what constitutes the ideal body type (Granberg, Simons, & Simons, 2009)
What is the sequence of physical changes at puberty for males? (7 sequential stages) (TSP, BP, CFO)
1) testes and scrotal sac
2) pubic hair
3) body growth
4) penis
5) change in voice
6) facial hair
7) Oil- and sweat-producing glands, acne
What happens at puberty for boys related to abnormal levels of estrogens that might cause embarrassment and body dissatisfaction?
During puberty, there are slight changes in the male breast to the embarrassment of many boys. This development is largely influenced by abnormal levels of estrogens.
For boys, what comes first fertility or an adult-like appearance.
For girls, what comes first fertility or an adult-like appearance.
boys are generally fertile before they have developed an adult-like appearance (Bogin, 2011); the opposite is true for girls.
What is the sequence of physical changes at puberty for females? (6 sequential stages) (BP BM UO)(Bill Pullman had a Bowel Movement at the University of Oregon)
1) Growth of breasts
2) Growth of pubic hair
3) Body growth
4) Menarche
5) Underarm hair
6) Oil- and sweat-producing glands
What is menarche?
The beginning of menstruation and is a relatively late development.
When does menarche occur in comparison to ovulation and full reproductive functioning? (MOF) (Made Of Feel)(as opposed to made of steel)
First: menarche
Second: 2 years later ovulation occurs
Third: full reproductive function does not occur until several years after menarche.
Unlike boys, therefore, girls generally appear physically mature before they are fertile.
1) The onset of puberty can occur as early as what age in girls?
2) The onset of puberty can occur as early as what age in boys?
3) The onset of puberty can occur as late as what age in girls?
4) The onset of puberty can occur as late as what age in boys?
5) In girls, the interval between the first sign of puberty and complete physical maturation can be as short as how many months?
6) In girls, the interval between the first sign of puberty and complete physical maturation can be as long as how many years?
7) In boys, the interval between the first sign of puberty and complete physical maturation can be as short as how many years?
8) In boys, the interval between the first sign of puberty and complete physical maturation can be as long as how many years?
5 6.5 13 13.5 18 months 6 2 5
By what age will an early-maturing, fast-maturing youngster complete pubertal maturation?
By what age will an
late-maturing, slow-maturing youngster complete pubertal maturation?
This range reveals developmental diversity!
10
18
Is there a relation between the age at which puberty BEGINS and the rate at which pubertal development PROCEEDS?
No relation between timing and tempo
Does the timing of puberty strong correlate with the height and weight of adulthood? If not, then what factor is strongly correlated with the height and weight of adulthood?
No! The correlate in this case is the height and weight during childhood.
Among Black girls, Mexican American girls, and White girls who typically begins puberty first, second, and third?
Black
Mexican American
White American
(This finding is NOT attributable solely to SES. Rather, to environmental factors such as being more frequently exposed to chemicals in the environment that stimulate earlier puberty, such as those contained in certain hair care products and cosmetics)
Every individual inherits a what to develop at a certain rate and to begin pubertal maturation at a certain time? But this predisposition is not a what age but rather an upper and lower age limit? Genetics determine the upper and lower age limits and the environment determines the timing and rate within those limits.
Predisposition
Fixed absolute
What 5 family-oriented factors contribute to puberty occurring somewhat earlier among girls?
1) Growing up in a father-absent family*
2) Growing up in a less cohesive family
3) Growing up in a conflict-ridden household
4) Growing up with a stepfather
5) Sexual abuse
One explanation for the finding that family conflict may accelerate pubertal maturation is that tension in the family may induce stress, which, in turn, may affect hormonal secretions in the adolescent, especially among girls who are genetically susceptible to this influence.
- the presence of a stepfather may expose the adolescent girl to pheromones that stimulate pubertal maturation. In general, among humans and other mammals, living in proximity to one’s close biological relatives appears to slow the process of pubertal maturation, whereas exposure to unrelated members of the other sex may accelerate it.
What is one of the best examples of how our social relationships can affect our biological functioning.
Women who live together—such as dormitory roommates—find that their menstrual periods begin to synchronize over time.
What role do genetic factors play in determining group differences in pubertal maturation?
(Researchers typically study group differences in puberty by comparing average ages of menarche in different regions.)
Genetic factors play an extremely small role in determining group differences in pubertal maturation (Eveleth & Tanner, 1990). Differences among countries in the average rate and timing of puberty are more likely to reflect differences in their environments than differences in their populations’ gene pools (Bogin, 2011).
Are there regional differences in the timing of puberty?
Menarche generally is earlier in countries where individuals are less likely to be malnourished or to suffer from chronic disease (Bogin, 2011). For example, in western Europe and in the United States, the median age of menarche ranges from about 12 to 13½ years. In Africa, however, the median age ranges from about 14 to 17 years
Researchers study environmental effects on pubertal timing in what 3 ways?
1) Looking at individual differences
2) looking at group differences
3) looking at secular trends or changes over time.
What 6 factors potentially explain the secular trends in pubertal timing over the past 2 centuries?
1) improved nutrition
2) better sanitation
3) better control of infectious diseases
4) increased rates of obesity, which affects leptin levels.
5) exposure to certain man-made chemicals in cosmetics, food, and the environment that affect development by mimicking actual pubertal hormones
6) increased exposure to artificial light, which affects melatonin secretion
What evidence indicates that the secular trend is valid? In most European countries, maturation has arrived earlier by about how many months per decade? For example, in Norway 150 years ago, the average age of menarche may have been about how many years? Today in Norway, menarche begins at approximately what ages? Similar declines have been observed over the same period in other industrialized nations and, more recently, in developing countries as well (Ma et al., 2009)
3 to 4
17
12 and 13
Why are children spending more time in the midst of puberty than ever before?
There is some evidence suggesting it is beginning earlier and taking longer to complete. In short, onset is earlier and duration is longer.
Why is the secular trend concerning for the positive development of adolescents?
As the age of puberty has dropped, the amount of time elapsed between the arousal of sensation seeking (puberty induces higher inclinations for sensation seeking) and the maturation of self control has grown, creating a larger window of vulnerability to risky behavior (your new car arrives on Monday but the breaks and all the safety features don’t arrive until Friday…good luck!) Consistent with this, as the age of puberty has fallen, rates of adolescent mortality have risen.
How does puberty affect behavior directly and indirectly?
Directly
1) puberty increases levels of testosterone which are directly linked to an increase in sex drive and sexual activity among adolescent boys.
Indirectly
1) puberty may change the adolescent’s self-image, which, in turn, may affect how he or she behaves. For example, a boy who has recently gone through puberty may feel more grown up as a result of his more adultlike appearance. This, in turn, may make him seek more independence from his parents. He may ask for a later curfew, a larger allowance, or the right to make decisions about things that previously were decided by his parents.
2) puberty specifically the physical changes of puberty often spark conflict between teenagers and their parents, in part because of the ways in which puberty affects the adolescent’s desire for autonomy.
3) puberty transforms the adolescent’s appearance, which, in turn, may elicit changes in how others react to the teenager. These changes in reactions may provoke changes in the adolescent’s behavior. An adolescent girl who has recently matured physically may find herself suddenly receiving the attention of older boys who had not previously paid her much heed. She may feel nervous about all the extra attention and confused about how she should respond to it. Moreover, she must now make decisions about how much time she wishes to devote to dating and how she should behave when out with someone who is sexually interested in her.
The impact of puberty on adolescents’ psychological functioning is to a great extent shaped by what?
social context in which puberty takes place.
How does puberty affect self esteem? It depends!
It varies by gender and ethnic group, with girls more adversely affected than boys and White girls at greatest risk for developing a poor body image.
Given the premium placed on thinness in contemporary American society , the increase in body dissatisfaction among White girls that takes place at puberty is, not surprisingly, linked to specific concerns that girls have about what 4 features of their bodies?
hips, thighs, waist, and weight
Self-esteem or self-image is reasonably what over time, with long and sturdy roots reaching back to childhood
Stable
One classic study, when adolescents’ moods were monitored repeatedly by electronic pagers, for example, how did their moods compare to the moods of adults?
Researchers found that their moods fluctuated during the course of the day more than the moods of adults.
