From Wikipedia, the free encyclopedia
Jump to: navigation, search
Puberty is the sexual development of children that makes them adults. This makes their bodies change.

Puberty is the sexual development of children into adults. A girl at puberty can become pregnant. A boy can make a girl pregnant if he has sex with her. Changes that occur to both sexes at puberty include sex organs growing and secondary sex characteristics, including boys' voices getting deeper and girls' breast growth. People in puberty can become sexually attracted to each other.

How the body controls puberty[change | change source]

The location of the pituitary gland is in orange. The gland makes hormones that cause both sexes' bodies to start puberty.

Puberty is begun and carried out by different hormones. Hormones are chemicals that tell parts of the body to do things. They are made by glands in the body. The following things happen at puberty:[1]

  1. The hypothalamus gland sends gonadotropin-releasing hormone (GnRH) into a nearby gland called the pituitary gland.
  2. GnRH causes cells in the pituitary gland to make two hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH).[2] LH and FSH are types of hormones called gonadotropins. The bloodstream carries these hormones around the body.
  3. LH and FSH make the gonads grow larger and start producing their own hormones, estradiol and testosterone. A girl's gonads are her ovaries. A boy's gonads are his testicles (also called testes). Ovaries produce more estradiol. Testicles produce more testosterone. Estradiol and testosterone are types of hormones called steroid hormones, which are also made by the body's two adrenal glands.
  4. When the amount of estradiol and testosterone in the body increases, various body parts change.

When puberty starts and ends[change | change source]

Puberty usually begins sooner in girls than in boys.[3] Usually, girls begin puberty at age 10. Boys usually begin it at age 11–12.[4][5][6] Girls usually complete puberty by 15,[7] boys by 16.[5][8] But this varies.[9] The major landmark of puberty for females is menarche (the start of menstruation), which occurs mostly at 12–13.[10][11][12] For males, it is the first ejaculation, which occurs mostly at 13.[13] In the 2000s, the average age when children, especially girls, hit puberty is lower than in the 1800s, due to improved nutrition.[14]

Body changes in males[change | change source]

For most boys, puberty takes place at ages 11-16. At the end of puberty, a boy is usually about 10 to 3 centimetres (3.9 to 1.2 in) taller, 7 to 29 kilograms (15 to 64 lb) heavier, and stronger. He is able to make women pregnant.[15] The sex organs of males grow bigger during puberty. Their penis gets larger.

Sex organs grow bigger[change | change source]

The first sign of puberty in boys is that their testicles (also called testes) and scrotum (where the testicles are) grow bigger.[16] Before puberty, each testicle is about 1.5 to 2 centimetres (0.59 to 0.79 in) long and has a volume of about 2 to 3 cubic centimetres (0.12 to 0.18 cu in). About 6 years after puberty starts, the testicles reach their adult size.[17] The volume of an average adult man's testicle is about 18 to 20 cubic centimetres (1.1 to 1.2 cu in). However, it is normal for some men to have testicles smaller than this size, and for other men to have larger testicles.[18]

The testicles have two main jobs: making hormones and sperm. The testicles make the hormone testosterone, which spreads around the body. This causes the changes in the body that make a boy become a man. Testosterone also makes a man desire sex. One year after puberty begins, when boys urinate after waking up in the morning, sperm is in the urine. When a boy is about 13 years old, his testicles will have grown enough that he may be fertile (able to make a woman pregnant). The sperm in the testicles mixes with other liquids in the body to form a whitish or yellowish sticky fluid called semen. At puberty, two glands in the body called the seminal vesicles and prostate also grow bigger.[19] These glands make a lot of the liquid that is in semen.

When a man is sexually excited, he has an erection. That means that his penis becomes bigger, longer and harder. A male becomes sexually excited if thinks about sex or sees a good-looking person. At puberty, boys also have erections for no reason.[20]

When a man's penis is sexually stimulated for some time, he has ejaculates, has an orgasm and semen shoots out from the penis. A boy's first ejaculation usually happens about one year after he begins puberty. For some boys, the first ejaculation takes place when they are sleeping. This is called a nocturnal emission or a wet dream. It happens without the boy's control, often when he is having a dream about sex. Scientists think wet dreams are the body's way of removing too much semen.[source?] A male masturbates when he rubs his penis to make himself feel good sexually.

When a boy starts to ejaculate, he usually produces only a small amount of semen. The semen is different from what an adult man produces. It is usually clear and stays sticky. It either has no sperm in it, or sperm that do not move properly or at all. A boy's semen only becomes like an adult man's semen about two years after his first ejaculation.[21]

Body hair and skin changes[change | change source]

This picture shows hair growth on the male body at and after puberty.
The face starts growing hair during puberty.

Soon after a boy's testicles and penis start to grow, pubic hair appears. Pubic hair grows on the part of the body where the penis is. Pubic hair is shorter, curlier and rougher than hair on the head. It usually starts growing on the abdomen above the penis where it joins the body. There may be some hair on the scrotum. After about six months to one year, there will be a large triangle of hair in the pubic region. Within 3-4 years after puberty begins, there is a lot of pubic hair in the area above the penis. Later on, pubic hair also grows on the abdomen upwards towards the navel and on the insides of the thighs.[22]

About two years after pubic hair starts to appear,[22] hair also grows on other parts of the body, including the armpits, around the anus, the top lip, the sides of the face next to the ears, around the nipples, and the lower part of the face.

The hair on the arms, legs, chest, abdomen and back may also become thicker. Different men have different amounts of body hair. Boys can begin shaving when hair starts growing on their faces.

A larger amount of male hormones in the body cause sweating, which gives it a more adult smell. The hormones also cause sebaceous glands in the skin to make more sebum, a type of oil that keeps skin from getting too dry. Sebum and dead skin cells can mix with a type of germ called bacteria and block pores in the skin. This causes a skin problem called acne. Some people get acne at puberty. When a person has acne, he gets swellings on his skin called blackheads, whiteheads and pimples. Blackheads and whiteheads are painless, but pimples can be painful. They usually form on the face but can also appear on the neck, shoulders, upper back and chest. Oil glands on the scalp also make a lot of sebum. This can cause dandruff, in which small white bits of skin fall from the scalp.[23]

Voice changes[change | change source]

During puberty, a boy's voicebox grows larger. This makes the Adam's apple larger. As the voicebox grows, the vocal cords become longer and thicker and vibrate more slowly. This makes the voice lower in pitch. When this happens, it is sometimes said that the boy's voice has "broken". It actually does not happen overnight but over time. On average, a boy's voice normally reaches its adult sound about age 15.[24]

Body growth[change | change source]

Towards the end of puberty, boys have a growth spurt (grow taller) for about 2-3 years. When the growth spurt is fastest,some people grow 10 centimetres (3.9 in) or more a year. This happens about 2 years after puberty starts, usually from ages 13-15. A boy reaches the end of his growth at about 18 years. He will not grow much taller.[1][25]

Boys grow slower than girls, but for longer. Thus most men are taller than women.[25] By puberty's end, men have heavier bones and more muscle than women. In an average adult man, muscle makes up 50% of his weight. Fat makes up 15% of his weight. Because men have less body fat than women, their hips do not grow bigger. Some bones like those in the jaw and shoulders grow more in males than in females. That is why males have wider faces and shoulders but narrower hips.[26]

Body changes in females[change | change source]

The changes in girls' bodies during puberty usually take place during ages 8-15 years. After puberty, they have breasts and pubic hair, menstruate every month, and can get pregnant. They usually have reached full adult height.[27] They develop breasts from about age 9 to age 15.

Body hair and skin changes[change | change source]

The brown parts of the picture on the left show where hair grows on a woman's body. Thicker hair is shown by the dark brown parts, and thinner hair by the light brown parts. As you can see from the picture on the right, men generally have more body hair than women.

At about age 8-14, pubic hair begins to grow along the labia (the "lips" of the vulva). This usually starts a few months after the breasts start growing.[28][29] At first the hair is thin and straight instead of curly, and there is not much of it.[27][29] Within a year, the pubic hair becomes rough, dark and curly and grows in a triangle shape in the pubic region. About one year after pubic hair begins appearing, underarm hair also grows. The hair on the arms and legs also gets thicker, and some girls may have hair appearing on their upper lip and in front of their ears.[30] Like boys, higher amounts of hormones in the body cause girls' sweat to change. This gives them a more adult body smell. The hormones also cause the skin to produce more oil, which can cause acne.

Body growth[change | change source]

Because of more hormones in the body, girls start to have more fat in their breasts, abdomen, hips and thighs. At 10 years, the average girl has 6% more body fat than the average boy. By the end of puberty she has 50% more.[31] The fat ensures a baby inside a pregnant woman has enough nutrients. The bones in the pelvis move further apart to make room for a larger uterus and ovaries, and so there is space for a baby to grow in the uterus and to pass out of the body when born. The extra fat and wider hip bones girls have give them a curvier shape.[32] Girls have a growth spurt at puberty that usually ends about age 17 years. [33] In the first year after puberty begins, they grow about 8 centimetres (3.1 in). They grow even faster the next year or so. The growth slows down and almost stops when they start menstruating. After a girl's periods begin, she usually does not grow more than 5 centimetres (2.0 in) taller.[30]

Related pages[change | change source]

References[change | change source]

  1. 1.0 1.1 Steven Dowshen (reviewer) (April 2007). "Everything you wanted to know about puberty". TeensHealth, The Nemours Foundation's Center for Children's Health Media. Retrieved 29 November 2008.
  2. T.M. Plant (January 2001). "Leptin, Growth Hormone, and the Onset of Primate Puberty". J. Clin. Endocrinol. Metab. 86 (1): 458–460.
  4. "When is puberty too early?". Duke University Hospital. Retrieved October 10, 2012.
  5. 5.0 5.1 "For girls, puberty begins around 10 or 11 years of age and ends around age 16. Boys enter puberty later than girls-usually around 12 years of age-and it lasts until around age 16 or 17." "Teenage Growth & Development: 11 to 14 Years".
  6. Solway, Andrew Exercise: From Birth to Old Age page 26
  7. Jaclyn McComb, Mimi Zumwait, Reid Norman The Active Female Health Issues Throughout the Life Span page 223
  8. "Teenage Growth & Development: 15 to 17 Years".
  9. A.J. Giannini; A.E. Slaby (1981). "A Speculation on Oranges, Puberty, Marriage Contracts and Frozen Food". M.D. 25 (5): 51–52.
  10. Anderson SE, Dallal GE, Must A (2003). "Relative weight and race influence average age at menarche: results from two nationally representative surveys of US girls studied 25 years apart". Pediatrics 111 (4 Pt 1): 844–50. doi:10.1542/peds.111.4.844 . PMID 12671122 .
  11. Al-Sahab B, Ardern CI, Hamadeh MJ, Tamim H (2010). "Age at menarche in Canada: results from the National Longitudinal Survey of Children & Youth". BMC Public Health (BMC Public Health) 10: 736. doi:10.1186/1471-2458-10-736 . PMC 3001737 . PMID 21110899 .
  12. Hamilton-Fairley, Diana. Obstetrics and Gynaecology (Second ed.). Blackwell Publishing.
  13. (Jorgensen & Keiding 1991).
  14. Guillette EA et al (2006). "Altered breast development in young girls from an agricultural environment". Environ. Health Perspect. 114 (3): 471–5. PMC 1392245 . PMID 16507474 .
  15. Ann Byers (2007). "How Do Boys' Bodies Change during Puberty?". Frequently Asked Questions about Puberty. New York, N.Y.: Rosen Publishing. pp. 16–25 at 16. ISBN 978-1-4042-0966-4 .
  16. Dennis M. Styne (2002). M.A. Sperling. ed. Pediatric Endocrinology (2nd ed. ed.). Philadelphia, Pa.: Saunders. p. 598. ISBN 9780721695396 .
  17. Kenneth W. Jones (2006). Smith's Recognizable Patterns of Human Malformation. St. Louis, Mo.: Elsevier Saunders. ISBN 9780721606156 .
  18. Marshall, Human Growth, p. 180.
  19. Steve Dowshen (reviewer) (November 2007). "Male reproductive system". TeensHealth, The Nemours Foundation's Center for Children's Health Media. Retrieved 29 November 2008.
  20. Byers, Frequently Asked Questions about Puberty, p. 23.
  21. Z. Janczewski; L. Bablok (1985). "Semen Characteristics in Pubertal Boys: I. Semen Quality after First Ejaculation". Archives of Andrology 15: 199–205.
  22. 22.0 22.1 Byers, Frequently Asked Questions about Puberty, p. 18.
  23. Byers, Frequently Asked Questions about Puberty, pp. 22–23.
  24. Byers, Frequently Asked Questions about Puberty, pp. 21–22.
  25. 25.0 25.1 Byers, Frequently Asked Questions about Puberty, p. 19.
  26. Byers, Frequently Asked Questions about Puberty, p. 21.
  27. 27.0 27.1 J. Jeff Malta. "5 stages of puberty – girls?". Puberty 101. Retrieved 1 December 2008.
  28. Marshall, Human Growth, p. 188.
  29. 29.0 29.1 J.M. Tanner; P.S. Davies (September 1985). "Clinical Longitudinal Standards for Weight and Height Velocity for North American Children". Journal of Pediatrics 107 (3): 317–329.
  30. 30.0 30.1 Byers, Frequently Asked Questions about Puberty, p. 28.
  31. Neslihan Gungor; S.A. Arslanian (2002). "Nutritional Disorders: Integration of Energy Metabolism and its Disorders in Childhood". In M.A. Sperling (ed.). Pediatric Endocrinology (2nd ed.). Philadelphia, Pa.: Saunders. pp. 689–724 at 699–700. ISBN 9780721695396 .
  32. Byers, Frequently Asked Questions about Puberty, p. 29.
  33. Powell, Jillian Puberty Britannica Digital Learning page 7

Sources[change | change source]

  • Byers, Ann (2007). Frequently asked questions about puberty. New York, N.Y.: Rosen Publishing. ISBN 978-1-4042-0966-4
  • Chen, Chuansheng; Farruggia, Susan (2002). "Culture and adolescent development [Unit 11, Chapter 2]". Online readings in psychology and culture. Ed. W.J. Lonner [et al.]. Bellingham, Wash.: Center for Cross-Cultural Research, Western Washington University. 
  • Marshall, William A.; J.M. Tanner (1986). Human growth: a comprehensive treatise (2nd ed.). New York, N.Y.: Plenum Press. ISBN 978-0-306-41952-2
  • Fass, Paula S. (2004). "Puberty". Encyclopedia of children and childhood: in history and society. Farmington Hills, Mich.: Thomson Gale. 

Videos[change | change source]

Other websites[change | change source]