WordNet

not of major importance; "played a secondary role in world events"
the defensive football players who line up behind the linemen
being of second rank or importance or value; not direct or immediate; "the stone will be hauled to a secondary crusher"; "a secondary source"; "a secondary issue"; "secondary streams"
belonging to a lower class or rank
depending on or incidental to what is original or primary; "a secondary infection"
tell the sex (of young chickens)
the properties that distinguish organisms on the basis of their reproductive roles; "she didnt want to know the sex of the foetus" (同)gender, sexuality
all of the feelings resulting from the urge to gratify sexual impulses; "he wanted a better sex life"; "the film contained no sex or violence" (同)sexual urge
either of the two categories (male or female) into which most organisms are divided; "the war between the sexes"
typical or distinctive; "heard my friends characteristic laugh"; "red and gold are the characteristic colors of autumn"; "stripes characteristic of the zebra"
any measurable property of a device measured under closely specified conditions (同)device characteristic
a distinguishing quality
the integer part (positive or negative) of the representation of a logarithm; in the expression log 643 = 2.808 the characteristic is 2
having sexual differentiation
characterized by sexuality; "highly sexed"

PrepTutorEJDIC

『第2の』,2番目の;(…の)次の《+『to』+『名』》 / 派生的な,二次的な,あまり重要でない / 中等学校[教育]の / 二次電流の
〈U〉〈C〉『性』,性別 / 《the~》《形容詞を伴い集合的に》『男性』,『女性』 / 〈U〉(男女(雌雄)間の)相違[の意識] / 〈U〉性に関する事柄(情報) / 〈U〉性交 / 〈ひよこなど〉‘の'性別を見分ける
『特有の』,独特の / 『特性』,特色,特微

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/09 17:09:30」(JST)

wiki en

A peacock displays his long, colored feathers, an example of his secondary sex characteristics.

Secondary sex characteristics are features that appear during puberty in humans and sexual maturity in other animals, especially those that distinguish the two sexes of a species, but that are not directly part of the reproductive system, as the primary sex characteristics are. They are believed to be the product of sexual selection for traits which give an individual an advantage over its rivals in courtship and aggressive interactions.^{[citation needed]} They are distinguished from the primary sex characteristics — the sex organs — which are directly necessary for reproduction to occur.

Well-known secondary sex characteristics include manes of male lions and long feathers of male peacocks. Other dramatic examples include the tusks of male narwhals, enlarged proboscises in male elephant seals and proboscis monkeys, the bright facial and rump coloration of male mandrills, and horns in many goats and antelopes. Male birds and fish of many species have brighter coloration or other external ornaments. Differences in size between sexes are also considered secondary sexual characteristics.

In humans, visible secondary sex characteristics include enlarged breasts of females and facial hair and adam's apple on males.

Evolutionary roots

Illustration from The Descent of Man and Selection in Relation to Sex by Charles Darwin showing the tufted coquette, Lophornis ornatus, female on left, ornamented male on right.

Charles Darwin hypothesized that sexual selection, or competition within a species for mates, can explain observed differences between sexes in many species.^[1] Biologists today distinguish between "male-to-male combat" and "mate choice", usually female choice of male mates. Sexual characteristics due to combat are such things as antlers, horns, and greater size. Characteristics due to mate choice, often referred to as ornaments, include brighter plumage, coloration, and other features that have no immediate purpose for survival or combat.

Ornamentation might arise because of some arbitrary female preference that is initially amplified by random genetic drift, eventually being reinforced by active selection for males with the appropriate ornament. This is known as the sexy son hypothesis.^[2] An alternative hypothesis is that some of the genes that enable males to develop impressive ornaments or fighting ability may be correlated with fitness markers such as disease resistance or a more efficient metabolism. This idea is known as the good genes hypothesis.

In humans

Anatomical characteristics of the human male and female

Sexual differentiation begins during gestation, when the gonads are formed. General habitus and shape of body and face, as well as sex hormone levels, are similar in prepubertal boys and girls. As puberty progresses and sex hormone levels rise, differences appear, though puberty causes some similar changes in male and female bodies.

Male levels of testosterone directly induce growth of the testicles and penis, and indirectly (via dihydrotestosterone (DHT)) the prostate. Estradiol and other hormones cause breasts to develop in females. However, fetal or neonatal androgens may modulate later breast development by reducing the capacity of breast tissue to respond to later estrogen.

Males

In males, testosterone directly increases size and mass of muscles, vocal cords, and bones, deepening the voice, and changing the shape of the face and skeleton. Converted into DHT in the skin, it accelerates growth of androgen-responsive facial and body hair, but may slow and eventually stop the growth of head hair. Taller stature is largely a result of later puberty and slower epiphyseal fusion.

Growth of body hair, including underarm, abdominal, chest hair and pubic hair. Loss of scalp hair due to androgenic alopecia can also occur.
Greater mass of thigh muscles in front of the femur, rather than behind it as is typical in mature females
Growth of facial hair
Enlargement of larynx (Adam's apple) and deepening of voice^[3]
Increased stature; adult males are taller than adult females, on average
Heavier skull and bone structure
Increased muscle mass and strength
Larger hands, feet and nose than women, prepubescent boys, and girls
Larger bodies
Square face
Small waist, but wider than females
Broadening of shoulders and chest; shoulders wider than hips^[4]
Increased secretions of oil and sweat glands, often causing acne and body odor^[3]
Coarsening or rigidity of skin texture due to less subcutaneous fat
Higher waist-to-hip ratio than prepubescent or adult females or prepubescent males, on average
Lower bodyfat percentage than prepubescent or adult females or prepubescent males, on average
Enlargement (growth) of the penis

Females

In females, breasts are a manifestation of higher levels of estrogen; estrogen also widens the pelvis and increases the amount of body fat in hips, thighs, buttocks, and breasts. Estrogen also induces growth of the uterus, proliferation of the endometrium, and menses.

Enlargement of breasts and erection of nipples.^[4]
Growth of body hair, most prominently underarm and pubic hair
Greater development of thigh muscles behind the femur, rather than in front of it
Widening of hips;^[5] lower waist to hip ratio than adult males
Smaller hands and feet than men
Elbows that hyperextend 5-8° more than men^[6]
Rounder face
Smaller waist than men
Upper arms approximately 2 cm longer, on average, for a given height^[7]
Changed distribution in weight and fat; more subcutaneous fat and fat deposits, mainly around the buttocks, thighs, and hips
Labia minora, the inner lips of the vulva, may grow more prominent and undergo changes in color.^[8]

Notes

^ Darwin, C. (1871) The Descent of Man and Selection in Relation to Sex John Murray, London
^ Weatherhead PJ, Robertson RJ; Robertson (Feb 1979). "Offspring quality and the polygyny threshold: 'The sexy son hypothesis'". Am Nat. 113 (2): 201–8. doi:10.1086/283379.
^ ^a ^b Sexual reproduction
^ ^a ^b "Secondary Characteristics". hu-berlin.de.
^ "Sexual Maturity". Technical Issues in Reproductive Health. Columbia University. May 2, 2008.
^ Amis AA, Miller JH (Dec 1982). "The elbow". Clinics in rheumatic diseases 8 (3): 571–93. PMID 7184689.
^ Manwatching: A Field Guide to Human Behaviour, 1977, Desmond Morris
^ Lloyd, Jillian et al. "Female Genital Appearance: 'Normality' unfolds" British Journal of Obstetrics and Gynecology. Vol 12, Issue 5. May 2005

References

Judson, Olivia (2003). Dr. Tatiana's Sex Advice to All Creation: Definitive Guide to the Evolutionary Biology of Sex. London: Vintage. ISBN 978-0-09-928375-1.

UpToDate Contents

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1. 正常思春期 normal puberty
2. 思春期遅発症の診断および治療 diagnosis and treatment of delayed puberty
3. 思春期早発症の定義、原因、および評価 definition etiology and evaluation of precocious puberty
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5. 小児および思春期における性同一性障害のマネージメントの概要 overview of the management of gender nonconformity in children and adolescents

English Journal

Reproductive and histopathological effects in wild fish inhabiting an effluent-dominated stream, Wascana Creek, SK, Canada.

Tetreault GR, Bennett CJ, Cheng C, Servos MR, McMaster ME.SourceDepartment of Biology, University of Waterloo, 200 University Ave W., Waterloo, ON, N2L 3G1, Canada; Ecosystem Health Assessment, Environment Canada, 867 Lakeshore Rd., Burlington, ON, L7R 4A6, Canada.
Aquatic toxicology (Amsterdam, Netherlands).Aquat Toxicol.2012 Apr;110-111:149-61. Epub 2012 Jan 13.
During the winter low flow periods, Wascana Creek, Saskatchewan, Canada, can be 100% treated municipal wastewater downstream of the City of Regina's Wastewater Treatment Plant. The objective of this study was to determine if exposure to municipal effluent affects the health and reproductive developm
PMID 22307007

Sex hormone replacement in Turner syndrome.

Trolle C, Hjerrild B, Cleemann L, Mortensen KH, Gravholt CH.SourceDepartment of Endocrinology and Internal Medicine and Medical Research Laboratories, Aarhus University Hospital, 8000, Aarhus C, Denmark.
Endocrine.Endocrine.2012 Apr;41(2):200-19. Epub 2011 Dec 7.
The cardinal features of Turner syndrome (TS) are short stature, congenital abnormalities, infertility due to gonadal dysgenesis, with sex hormone insufficiency ensuing from premature ovarian failure, which is involved in lack of proper development of secondary sex characteristics and the frequent o
PMID 22147393

Japanese Journal

青少年における性に関する情報源と性に対するイメージの関連性

河村洋子
熊本大学政策研究 2, 55-66, 2011-03-25
… This study examined how Japanese adolescents use sexual information sources and explored the relationship between these information sources and images of sex. … I conducted secondary data analyses on the data from the 6th Waves of Japanese Adolescents' Sexual Behavior Survey, which was originally conducted in 2005. … The results showed that personal characteristics are related to the types of sexual information sources and ways of choosing them. …
NAID 110008455558

二次性徴の異常 (特集子どもの臨床検査--症候から診断・治療へ) -- (症候からみる臨床検査の進めかた)

田島敏広
小児科診療 74(-) (879), 57-60, 2011
NAID 40018815378

Related Pictures

★リンクテーブル★

リンク元	「二次性徴」
関連記事	「secondary」「characteristic」「sex」「sex characteristics」

「二次性徴」

　　[★]

英: secondary sex characteristics, secondary sex characters, secondary sexual characters secondary sexual characteristics
同: 第二次性徴
関: 思春期、一次性徴第一次性徴、性徴、タナー分類、

小児の発育と年齢

QB.O-26 SPE.11

♀： 9-18歳　　→　小学4年～
♂：10-20歳　　→　小学5年～

男児	年齢	女児
	8～9	子宮
精巣腫大	10～11	乳房
	11～12	恥毛、身長増加促進
恥毛、身長増加促進	12～13	腋毛
	13～14	初経
腋毛	14～15	正常月経
精子成熟	15～16
	16～17	骨端線閉鎖
骨端線閉鎖	18～20

陰茎発育は精巣の発育に次いで起こる。

男性

10歳頃から

女性

QB.Q-241

FSH：10歳ごろから上昇。14歳頃に成人レベル。エストロゲンもこれに伴って上昇。
LH：10歳ごろから分泌がみられる。

LH surge：エストロゲン増加は9-10歳から見られるが、エストロゲンの濃度が低く初経後1-2年はLH surgeが見られない。

20歳未満では無排卵性月経が半数以上で、排卵性周期は20-25歳で確立

臨床関連

思春期早発症：8歳未満で第二次性徴を認める
思春期遅発症：14歳を過ぎても第二次性徴を認めない

「secondary」

　　[★]

adj.

(地位・価値・重要性などが)第2の、2番目の、(～の)次の(to)。二次的な、従位の

Postmortem examination of patients with such obstructions without a history of clinical manifestations of myocardial ischemia often shows macroscopic scars secondary to MI in regions supplied by diseased coronary arteries, with or without collateral circulation.

in the past the commonest cause of death has been venous thrombosis followed by infection secondary to severe neutropenia and hemorrhage secondary to severe thrombocytopenia.(HIM.661)(重度の好中球減少に次ぐ感染と血小板減少に次ぐ出血に続発する静脈血栓症が昔の最も一般的な死因であった)