puberty

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Puberty

 

Definition

Puberty is the period of human development during which physical growth and sexual maturation occurs.

Description

Beginning as early as age eight in girls-and two years later, on average, in boys—the hypothalamus (part of the brain) signals hormonal change that stimulates the pituitary. In turn, the pituitary releases its own hormones called gonadotrophins that stimulate the gonads and adrenals. From these glands come a flood of sex hormones—androgens and testosterone in the male, estrogens and progestins in the female-that regulate the growth and function of the sex organs. It is interesting to note that the gonadotrophins are the same for males and females, but the sex hormones they induce are different.
In the United States, the first sign of puberty occurs on average at age 11 in girls, with menstruation and fertility following about two years later. Boys lag behind by about two years. Puberty may not begin until age 16 in boys and continue in a desultory fashion on past age 20. In contrast to puberty, adolescence is more of a social/cultural term referring to the interval between childhood and adulthood.

Diagnosis

Puberty has been divided into five Sexual Maturity Rating (SMR) stages by two doctors, W. Marshall and J. M. Tanner. These ratings are often referred to as Tanner Stages 1-5. Staging is based on pubic hair growth, on male genital development, and female breast development. Staging helps determine whether development is normal for a given age. Both sexes also grow axillary (arm pit) hair and pimples. Males develop muscle mass, a deeper voice, and facial hair. Females redistribute body fat. Along with the maturing of the sex organs, there is a pronounced growth spurt averaging 3-4 in (8-10 cm) and culminating in full adult stature. Puberty can be precocious (early) or delayed. It all depends upon the sex hormones.
Puberty falling outside the age limits considered normal for any given population should prompt a search for the cause. As health and nutrition have improved over the past few generations, there has been a gradual decrease in the average age for the normal onset of puberty.
  • Excess hormone stimulation is the cause for precocious puberty. It can come from the brain in the form of gonadotrophins or from the gonads and adrenals. Overproduction may be caused by functioning tumors or simple overactivity. Brain overproduction can also be the result of brain infections or injury.
  • Likewise, delayed puberty is due to insufficient hormone. If the pituitary output is inadequate, so will be the output from the gonads and adrenals. On the other hand, a normal pituitary will overproduce if it senses there are not enough hormones in the circulation.
  • There are several congenital disorders (polyglandular deficiency syndromes) that include failure of hormone output. These children do not experience normal puberty, but it may be induced by giving them the proper hormones at the proper time.
  • Finally, there are in females abnormalities in hormone production that produce male characteristics—so called virilizing syndromes. Should one of these appear during adolescence, it will disturb the normal progress of puberty. Notice that virilizing requires abnormal hormones in the female, while feminizing results from absent hormones in the male. Each embryo starts out life as female. Male hormones transform it if they are present.
Delayed or precocious puberty requires measurement of the several hormones involved to determine which are lacking or which are in excess. There are blood tests for each one. If a tumor is suspected, imaging of the suspect organ needs to be done with x rays, computed tomography scans (CT scans), or magnetic resonance imaging (MRI).

Treatment

Puberty is a period of great stress, both physically and emotionally. The psychological changes and challenges of puberty are made infinitely greater if its timing is off.
In precocious puberty, the offending gland or tumor may require surgical attention, although there are several drugs now that counteract hormone effects. If delayed, puberty can be stimulated with the correct hormones. Treatment should not be delayed because necessary bone growth is also affected.

Prognosis

Properly administered hormones can restore the normal growth pattern.

Resources

Books

Fauci, Anthony S., et al., editors. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 1997.

Key terms

Adrenals — Glands on top of the kidneys that produce four different types of hormones.
Computed tomography scan (CT) — A method of creating images of internal organs using x rays.
Embryo — The life in the womb during the first two months.
Gonads — Glands that make sex hormones and reproductive cells-testes in the male, ovaries in the female.
Hormone — A chemical produced in one place that has an effect somewhere else in the body.
Hypothalamus — Part of the brain located deep in the center of the skull and just above the pituitary.
Magnetic resonance imaging (MRI) — A method of creating images of internal organs. Magnetic resonance imaging (MRI) uses magnet fields and radio-frequency signals.
Pituitary — The "master gland" of the body, controlling many of the others by releasing stimulating hormones.
Syndrome — A collection of abnormalities that occur often enough to suggest they have a common cause.

puberty

 [pu´ber-te]
the period during which the secondary sex characters begin to develop and the capability of sexual reproduction is attained. In girls it is marked by broadening of the hips, development of the breasts, appearance of pubic hair, and onset of menstruation. In boys it is marked by broadening of the shoulders, deepening of the voice, and appearance of pubic and facial hair. Girls usually reach puberty between age 11 and 13, and boys between 13 and 15, although the timing varies widely.
precocious puberty unusually early sexual maturation, defined as before age 8 in girls and 9 in boys; both isosexual and contrasexual types occur. It is usually hormonal (central or true precocious p.,) although occasionally it occurs in otherwise normal children, such as those with a family history of it (constitutional precocious p.).

pu·ber·ty

(pyū'bĕr-tē),
Sequence of events by which a child becomes a young adult, characterized by the beginning of gonadotropin secretion, gametogenesis, secretion of gonadal hormones, development of secondary sexual characteristics and reproductive functions; sexual dimorphism is accentuated. In girls, the first signs of normal puberty may be evident after age 8 with the process largely completed by age 16; in boys, normal puberty commonly begins at age 9 and is largely completed by age 18. Ethnic and geographic factors may influence the time at which various events typical of puberty occur.
[L. pubertas, fr. puber, grown up]

puberty

/pu·ber·ty/ (pu´ber-te) the period during which the secondary sex characters begin to develop and the capability of sexual reproduction is attained.pu´beralpu´bertal
central precocious puberty  precocious puberty due to premature hypothalamic-pituitary-gonadal maturation; it is always isosexual and involves not only development of secondary sex characters but also development of the gonads. Increases in height and weight and osseous maturation are accelerated, and early closing of the epiphyses leads to short stature.
precocious puberty  the onset of puberty at an earlier age than normal, defined as before age 8 in girls and 9 in boys; it is usually hormonal, but occasionally occurs in otherwise normal children.

puberty

(pyo͞o′bər-tē)
n.
The stage of adolescence in which an individual becomes physiologically capable of sexual reproduction.

pu′ber·tal, pu′ber·al (-bər-əl) adj.

puberty

[p(y)o̅o̅′bərtē]
Etymology: L, pubertas, age of maturity
the period of life at which the ability to reproduce begins. It is a stage of development when genitalia reach maturity and secondary sex characteristics appear. The onset normally occurs in females between 9 and 13 years of age with the development of breasts and menarche. In males, puberty usually occurs between 12 and 14 years of age and is characterized by the ejaculation of sperm.

puberty

The point of life at which an adolescent begins to secrete adult levels of oestrogen and testosterone, resulting in adult sexual characteristics such as breasts, facial hair and public hair.

puberty

Adolescent medicine The period of hormone-induced transition to adolescence with development of 2º sex characteristics, ending in procreative maturity. See Early puberty, Precocious puberty, Premature puberty, Pseudopuberty, Pubertal delay.

pu·ber·ty

(pyu'bĕr-tē)
Sequence of events by which a child becomes a young adult, characterized by the beginning of gametogenesis, secretion of gonadal hormones, and development of secondary sexual characteristics and reproductive functions; sexual dimorphism is accentuated. In girls, the first signs of puberty may be evident at age 8 years with the process largely completed by age 16 years; in boys, puberty commonly begins at ages 10-12 years and is largely completed by age 18 years. Ethnic and geographic factors may influence the time at which various events typical of puberty occur.
[L. pubertas, fr. puber, grown up]

puberty

The period during which the sexual organs change from the infantile to the adult form, the SECONDARY SEXUAL CHARACTERISTICS develop and the bodily structure assumes adult proportions. Body weight may double during puberty. Puberty usually occurs between the ages of about 10 and 15 and is often associated with emotional upsets as the individual comes to terms with his or her new-found sexuality. Puberty is initiated by PITUITARY GLAND hormones called GONADOTROPHINS. These stimulate the testes and ovaries to produce sex hormones.

puberty

the period at the beginning of human adolescence when sexual maturity is attained.

puberty,

n the period of development in which the body becomes physically capable of reproduction, distinguished by the maturity of the gonads and appearance of secondary sexual characteristics.

pu·ber·ty

(pyu'bĕr-tē)
Sequence of events during which a child becomes a young adult, characterized by beginning of gonadotropin secretion, gametogenesis, secretion of gonadal hormones, development of secondary sexual characteristics and reproductive functions; sexual dimorphism is accentuated.
[L. pubertas, fr. puber, grown up]

puberty (pū´burtē),

n the age at which the reproductive system becomes functional, with concurrent development of secondary sex characteristics. Marked by increased estrogenic activity in the female and rise of androgenic activity in the male.

puberty

the time at which reproduction by an individual animal becomes possible for the first time; a term used infrequently in veterinary medicine but there is no other word which can substitute for it.

delayed puberty
varies widely between species and between breeds; negatively influenced by undernutrition and obesity.

Patient discussion about puberty

Q. which nutrition is recommended during puberty ?

A. puberty is a time when children experience growth spurt and their body needs a great amount of carbs, protein and vitamins and can skip the horrendous amount of fat that junk food supplies.
here is a good site about kids health that will give you some ideas what is good and what isn't in teen's nutrition-
http://kidshealth.org/teen/food_fitness/

More discussions about puberty
References in periodicals archive ?
Other girls are almost 13 before they hit their growth spurt.
It's also possible to lessen the pressure on young dancers by postponing high-profile competitions and examinations until the growth spurt has ended.
He found evidence of weekly changes, with growth spurts following no-growth periods that sometimes lasted more than 60 days (including occasional intervals of shrinkage).
Growth spurts are more frequent in 11 - to 13-year-old girls and 13-to 16-year-old boys, and can be detected by a physician or an experienced coach.
Crimes has been experiencing pains in her knees recently as a result of continued growth spurts.
The explosive stock advance teamed up with Thursday's strong performance to give Wall Street one of the biggest two-day growth spurts in blue-chip points ever: 460 points, or a 5 percent advance.
Yes, and they exhibit growth spurts every seven years, according to a new report.
This means that not only does sleep predict a growth spurt in length, but it also predicts an increase in weight and abdominal fat, implying an anabolic growth process.
No more than 1/4 inch should be allowed in shoes for the feet of a young dancer during a growth spurt.