Adolescence by Laurence Steinberg - Summary Adolescence

Adolescence by Laurence Steinberg Chapter 1 Key Vocabulary Endocrine system: the system of the body that produces, circulates, and regulates hormones Hormones: highly specialized substances secreted by one or more endocrine glands Glands: organs that stimulate particular parts of the body to respond in specific ways to particular hormones Gonadotropin-releasing hormone (GnRH) neurons: specialized neurons that are activated by certain pubertal hormones Set point: a physiological level or setting (ex: of a specific hormone) that the body attempts to maintain through a self-regulating system o 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 Feedback loop: a cycle through which two or more bodily functions respond to and regulate each other, such as that formed by the hypothalamus, the pituitary gland, and the gonads Pituitary gland: one of the chief glands responsible for regulating levels of hormones in the body Hypothalamus: a part of the brain that controls the functioning of the pituitary gland Gonads: the glands that secret sec hormones: in males, the testes; in females, the ovaries Androgens: a class of sex hormones secreted by the gonads, found in both sexes, but in higher levels among males than females Estrogens: a class of sex hormones secreted by the gonads, found in both sexes, but in higher levels among females than males following puberty HPG (hypothalamic-pituitary-gonadal) axis: the neurophysiological pathway that involves the hypothalamus, the pituitary gland, and the gonads o Set to maintain certain levels of androgens and estrogens Adrenarche: the maturation of the adrenal glands that takes place during adolescence o Contributes to the development of body odor, signaling the beginning of sexual maturation to others (also the beginning of sexual attraction) Cortisol: a hormone produced when a person is exposed to stress o At high and chronic levels it can cause brain cells to die Kisspeptin: a brain chemical believed to trigger the onset of puberty Leptin: a protein produced by the fat cells that may play a role in the onset of puberty through its impact on kisspeptin o Plays a critical role in the regulation of hunger and appetite, by suppressing our desire to eat when we’re full (tells our brain that we are “fat enough”) Melatonin: a hormone secreted by the brain that contributes to sleepiness and that triggers the onset of puberty through its impact on kisspeptin Adolescent growth spurt: the dramatic increase in height and weight that occurs during puberty Peak height velocity: the point at which the adolescent is growing most rapidly Epiphysis: the closing of the ends of the bones, which terminates growth after the adolescent growth spurt has been completed Tanner stages: a widely-used system that describes the five stages of pubertal development Menarche: the time of first menstruation, one of the most important changes to occur among females during puberty Pheromones: a class of chemicals secreted by animals that stimulate certain behaviors in other members of the species Secular trend: the tendency, over the past two centuries, for individuals to be larger in stature and to reach puberty earlier, primarily because of improvements in health and nutrition Cross-sectional study: a study that compares two or more groups of individuals at one point in time o Like different stages of puberty Longitudinal study: a study that follows the same group of individuals over time Delayed phase preference: a pattern of sleep characterized by later sleep and wake times, which usually emerges during puberty Basal metabolism rate: the minimal amount of energy used by the body during a resting state Body mass index (BMI): a measure of an individual’s body fat, the ratio of weight to height, used to gauge overweight and obesity o Divide weight (kg) by square of height (meters) Adolescent health care: a field of study and health care devoted to understanding the health care needs of individuals during the second decade of life Graduated driver licensing: a licensing system in which full adult driving privileges are not granted all at once to teen drivers, but phased in over time Puberty: An Overview The hormonal changes of puberty make us more responsive to stress  one reason why adolescence is a period of great vulnerability for the onset of many serious mental disorders o Adolescence is a time of heightened vulnerability to stress, not an inherently stressful time The more fat cells you have, and the more light to which you have been exposed during childhood, the more likely it is that you will go through puberty on the early side of your inherited propensity o This is why puberty starts earlier for obese children and children who grew up closer to the environment o Obese children have more body fat and therefore produce a lot more leptin, which stimulates kisspeptin production o Children who live closer to 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 o Exposure to artificial light (especially from electronics) can also suppress melatonin levels and hasten puberty o Due to evolution: used to have to have as many children as possible to ensure some of them survive (and store food in the winter) Changes are only partially because of hormones: many are actually due to the results of prenatal hormones