{"id":967,"date":"2020-07-06T16:19:55","date_gmt":"2020-07-06T16:19:55","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/adolescent\/?post_type=chapter&p=967"},"modified":"2021-06-03T13:51:12","modified_gmt":"2021-06-03T13:51:12","slug":"puberty-begins","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/adolescent\/chapter\/puberty-begins\/","title":{"raw":"Puberty Begins","rendered":"Puberty Begins"},"content":{"raw":"Puberty<\/strong>\u00a0is the period of rapid growth and sexual development that begins in adolescence and\u00a0starts at some point between ages 8 and 14. While the sequence of physical changes in puberty is predictable, the onset and pace of puberty vary widely. Every person\u2019s individual timetable for puberty is different and is primarily influenced by heredity; however, environmental factors\u2014such as diet and exercise\u2014also exert some influence.\r\n\r\nAdolescence has evolved historically, with evidence indicating that this stage is lengthening as individuals start puberty earlier and transition to adulthood later than in the past. Puberty today begins, on average, at age 10\u201311 years for girls and 11\u201312 years for boys. This average age of onset has decreased gradually over time since the 19th century by 3\u20134 months per decade, which has been attributed to a range of factors including better nutrition, obesity, increased father absence, and other environmental factors (Steinberg, 2013). Completion of formal education, financial independence from parents, marriage, and parenthood have all been markers of the end of adolescence and beginning of adulthood, and all of these transitions happen, on average, later now than in the past. In fact, the prolonging of adolescence has prompted the introduction of a new developmental period called emerging adulthood that captures these developmental changes out of adolescence and into adulthood, occurring approximately from ages 18 to 29 (Arnett, 2000).\r\n\r\n\"\"\"\"\r\n\r\nFigure 4.2.1<\/strong>. Major physical changes during puberty.\r\n

Hormonal Changes<\/span><\/h3>\r\nPuberty involves distinctive physiological changes in an individual\u2019s height, weight, body composition, and circulatory and respiratory systems, and during this time, both the adrenal glands and\u00a0sex glands mature. These changes are primarily influenced by hormonal activity.\u00a0Many hormones contribute to the beginning of puberty, but most notably,\u00a0a significant rush of\u00a0estrogen<\/strong>\u00a0for girls and\u00a0testosterone<\/strong>\u00a0for boys. Hormones play an\u00a0organizational role\u00a0<\/em>(priming the body to behave in a certain way once puberty begins) and an\u00a0activational role\u00a0<\/em>(triggering certain behavioral and physical changes). During puberty, the adolescent\u2019s hormonal balance shifts sharply towards an adult state; the process is triggered by the pituitary gland, which secretes a surge of hormonal agents into the bloodstream and initiates a chain reaction.\r\n\r\nPuberty occurs over two distinct phases, and the first phase,\u00a0adrenarche<\/strong>, begins at 6 to 8 years of age and involves increased production of adrenal androgens that contribute to a number of pubertal changes\u2014such as skeletal growth. The second phase of puberty,\u00a0gonadarche<\/strong>, begins several years later and involves increased production of hormones governing physical and sexual maturation.\r\n
\r\n

Sexual Maturation<\/h3>\r\n<\/div>\r\nDuring puberty, primary and secondary sex characteristics develop and mature.\u00a0Primary sex\u00a0characteristics<\/strong>\u00a0are organs specifically needed for reproduction\u2014the uterus and ovaries in females and testes in males.\u00a0Secondary sex\u00a0characteristics<\/strong>\u00a0are physical signs of sexual maturation that do not directly involve sex organs, such as the development of breasts and hips in girls, and growth of facial hair and a deepened voice in boys.\u00a0Both sexes experience the development of pubic and underarm hair, as well as increased development of sweat glands.\r\n\r\nThe male and female\u00a0gonads<\/strong>\u00a0are activated by the surge of the hormones discussed earlier, which puts them into a state of rapid growth and development. The testes primarily release testosterone, and the ovaries release estrogen; the production of these hormones increases gradually until sexual maturation is met.\r\n\r\nFor girls, observable changes begin with nipple growth and pubic hair. Then the body increases in height while fat forms, particularly on the breasts and hips. The first menstrual period (menarche<\/strong>) is followed by more growth, which is usually completed by four years after the first menstrual period began.\u00a0Girls experience menarche usually around 12\u201313 years old.\u00a0For boys, the usual sequence is growth of the testes, initial pubic-hair growth, growth of the penis, first ejaculation of seminal fluid (spermarche<\/strong>), appearance of facial hair, a peak growth spurt, deepening of the voice, and final pubic-hair growth. (Herman-Giddens et al., 2012).\u00a0Boys experience spermarche, the first ejaculation, around 13\u201314 years old.\r\n
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Physical Growth: The Growth Spurt<\/h3>\r\n<\/div>\r\nDuring puberty, both sexes experience a rapid increase in height and weight (referred to as a\u00a0growth spurt<\/strong>) over about 2-3 years resulting from the simultaneous release of growth hormones, thyroid hormones, and androgens.\u00a0Males experience their growth spurt about two years later than females. For girls, the growth spurt begins between 8 and 13 years old (average 10-11), with adult height reached between 10 and 16 years old. Boys begin their growth spurt slightly later, usually between 10 and 16 years old (average 12-13), and reach their adult height between 13 and 17 years old. Both nature (i.e., genes) and nurture (e.g., nutrition, medications, and medical conditions) can influence both height and weight.\r\n\r\nBefore puberty, there are nearly no differences between males and females in the distribution of fat and muscle. During puberty, males grow muscle much faster than females, and females experience a higher increase in body fat, and bones become harder and more brittle. An adolescent\u2019s heart and lungs increase in both size and capacity during puberty; these changes contribute to increased strength and tolerance for exercise.\r\n\r\nhttps:\/\/assessments.lumenlearning.com\/assessments\/16607\r\n\r\nhttps:\/\/assessments.lumenlearning.com\/assessments\/16608\r\n
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Reactions Toward Puberty and Physical Development<\/h3>\r\n<\/div>\r\nThe accelerated growth in different body parts happens at different times, but for all adolescents, it has a fairly regular sequence. The first places to grow are the extremities (head, hands, and feet), followed by the arms and legs, and later the torso and shoulders. This non-uniform growth is one reason why an adolescent body may seem out of proportion. Additionally, because rates of physical development vary widely among teenagers, puberty can be a source of pride or embarrassment.\r\n\r\nMost adolescents want nothing more than to fit in and not be distinguished from their peers in any way, shape, or form (Mendle, 2015). So when a child develops earlier or later than his or her peers, there can be long-lasting effects on mental health. Simply put,\u00a0beginning puberty earlier than\u00a0peers presents significant challenges, particularly for girls.\u00a0The picture for early-developing boys isn\u2019t as clear, but evidence suggests that they, too, eventually might suffer ill effects from maturing ahead of their peers. The biggest challenges for boys, however, seem to be more related to late development.\r\n\r\nEarly maturing boys tend to be stronger, taller, and more athletic than their later maturing peers. They are usually more popular, confident, and independent, but they are also at a greater risk for substance abuse and early sexual activity (Flannery, Rowe, & Gulley, 1993; Kaltiala-Heino, Rimpela, Rissanen, & Rantanen, 2001). Additionally, more recent research\u00a0found that while early-maturing boys initially had lower levels of depression than later-maturing boys, over time, they showed signs of increased anxiety, negative self-image, and interpersonal stress. (Rudolph, Troop-Gordon, Lambert, & Natsuaki, 2014).\r\n\r\nEarly maturing girls may be teased or overtly admired, which can cause them to feel self-conscious about their developing bodies. These girls are at increased risk of a range of psychosocial problems, including depression, substance use, and early sexual behavior (Graber, 2013).These girls are also at a higher risk for eating disorders, which we will discuss in more detail later in this module (Ge, Conger, & Elder, 2001; Graber, Lewinsohn, Seeley, & Brooks-Gunn, 1997; Striegel-Moore & Cachelin, 1999).\r\n\r\nLate maturing boys and girls (i.e., they develop more slowly than their peers) may feel self-conscious about their lack of physical development. Negative feelings are particularly a problem for late maturing boys, who are at a higher risk for depression and conflict with parents (Graber et al., 1997) and more likely to be bullied (Pollack & Shuster, 2000).\r\n\r\nhttps:\/\/youtu.be\/DWKWjpVsGng\r\n\r\nVideo 4.2.1.\u00a0<\/strong>Development in Adolescence\u00a0<\/em>provides an overview of physical changes during adolescence and psychosocial impacts.\r\n\r\nhttps:\/\/assessments.lumenlearning.com\/assessments\/16609\r\n

<\/h2>","rendered":"

Puberty<\/strong>\u00a0is the period of rapid growth and sexual development that begins in adolescence and\u00a0starts at some point between ages 8 and 14. While the sequence of physical changes in puberty is predictable, the onset and pace of puberty vary widely. Every person\u2019s individual timetable for puberty is different and is primarily influenced by heredity; however, environmental factors\u2014such as diet and exercise\u2014also exert some influence.<\/p>\n

Adolescence has evolved historically, with evidence indicating that this stage is lengthening as individuals start puberty earlier and transition to adulthood later than in the past. Puberty today begins, on average, at age 10\u201311 years for girls and 11\u201312 years for boys. This average age of onset has decreased gradually over time since the 19th century by 3\u20134 months per decade, which has been attributed to a range of factors including better nutrition, obesity, increased father absence, and other environmental factors (Steinberg, 2013). Completion of formal education, financial independence from parents, marriage, and parenthood have all been markers of the end of adolescence and beginning of adulthood, and all of these transitions happen, on average, later now than in the past. In fact, the prolonging of adolescence has prompted the introduction of a new developmental period called emerging adulthood that captures these developmental changes out of adolescence and into adulthood, occurring approximately from ages 18 to 29 (Arnett, 2000).<\/p>\n

\"\"\"\"<\/p>\n

Figure 4.2.1<\/strong>. Major physical changes during puberty.<\/p>\n

Hormonal Changes<\/span><\/h3>\n

Puberty involves distinctive physiological changes in an individual\u2019s height, weight, body composition, and circulatory and respiratory systems, and during this time, both the adrenal glands and\u00a0sex glands mature. These changes are primarily influenced by hormonal activity.\u00a0Many hormones contribute to the beginning of puberty, but most notably,\u00a0a significant rush of\u00a0estrogen<\/strong>\u00a0for girls and\u00a0testosterone<\/strong>\u00a0for boys. Hormones play an\u00a0organizational role\u00a0<\/em>(priming the body to behave in a certain way once puberty begins) and an\u00a0activational role\u00a0<\/em>(triggering certain behavioral and physical changes). During puberty, the adolescent\u2019s hormonal balance shifts sharply towards an adult state; the process is triggered by the pituitary gland, which secretes a surge of hormonal agents into the bloodstream and initiates a chain reaction.<\/p>\n

Puberty occurs over two distinct phases, and the first phase,\u00a0adrenarche<\/strong>, begins at 6 to 8 years of age and involves increased production of adrenal androgens that contribute to a number of pubertal changes\u2014such as skeletal growth. The second phase of puberty,\u00a0gonadarche<\/strong>, begins several years later and involves increased production of hormones governing physical and sexual maturation.<\/p>\n

\n

Sexual Maturation<\/h3>\n<\/div>\n

During puberty, primary and secondary sex characteristics develop and mature.\u00a0Primary sex\u00a0characteristics<\/strong>\u00a0are organs specifically needed for reproduction\u2014the uterus and ovaries in females and testes in males.\u00a0Secondary sex\u00a0characteristics<\/strong>\u00a0are physical signs of sexual maturation that do not directly involve sex organs, such as the development of breasts and hips in girls, and growth of facial hair and a deepened voice in boys.\u00a0Both sexes experience the development of pubic and underarm hair, as well as increased development of sweat glands.<\/p>\n

The male and female\u00a0gonads<\/strong>\u00a0are activated by the surge of the hormones discussed earlier, which puts them into a state of rapid growth and development. The testes primarily release testosterone, and the ovaries release estrogen; the production of these hormones increases gradually until sexual maturation is met.<\/p>\n

For girls, observable changes begin with nipple growth and pubic hair. Then the body increases in height while fat forms, particularly on the breasts and hips. The first menstrual period (menarche<\/strong>) is followed by more growth, which is usually completed by four years after the first menstrual period began.\u00a0Girls experience menarche usually around 12\u201313 years old.\u00a0For boys, the usual sequence is growth of the testes, initial pubic-hair growth, growth of the penis, first ejaculation of seminal fluid (spermarche<\/strong>), appearance of facial hair, a peak growth spurt, deepening of the voice, and final pubic-hair growth. (Herman-Giddens et al., 2012).\u00a0Boys experience spermarche, the first ejaculation, around 13\u201314 years old.<\/p>\n

\n

Physical Growth: The Growth Spurt<\/h3>\n<\/div>\n

During puberty, both sexes experience a rapid increase in height and weight (referred to as a\u00a0growth spurt<\/strong>) over about 2-3 years resulting from the simultaneous release of growth hormones, thyroid hormones, and androgens.\u00a0Males experience their growth spurt about two years later than females. For girls, the growth spurt begins between 8 and 13 years old (average 10-11), with adult height reached between 10 and 16 years old. Boys begin their growth spurt slightly later, usually between 10 and 16 years old (average 12-13), and reach their adult height between 13 and 17 years old. Both nature (i.e., genes) and nurture (e.g., nutrition, medications, and medical conditions) can influence both height and weight.<\/p>\n

Before puberty, there are nearly no differences between males and females in the distribution of fat and muscle. During puberty, males grow muscle much faster than females, and females experience a higher increase in body fat, and bones become harder and more brittle. An adolescent\u2019s heart and lungs increase in both size and capacity during puberty; these changes contribute to increased strength and tolerance for exercise.<\/p>\n

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