出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/09/16 22:59:17」(JST)
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ICD-10 | Q84.2 |
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ICD-9 | 757.4 |
DiseasesDB | 30821 |
Lanugo (/la·nu·go/,[1] from Latin lana “wool”) is very fine, soft, and usually unpigmented, downy hair on the body of a fetus or newborn baby. It is the first hair to be produced by the fetal hair follicles, and it usually appears on the fetus at about 5 months of gestation. It is normally shed before birth, around 7 or 8 months of gestation but is often present at birth and disappears on its own within a few days or weeks.[2]
Lanugo hair will invariably be shed by three to four months after birth. It is replaced by hair covering the same surfaces called vellus hair, but this hair is finer and more difficult to see. The more visible hair that continues into adulthood is called terminal hair. This forms in specific areas and is hormone dependant.[3]
During human development, the lanugo grows on fetuses as a normal part of gestation, but is usually shed and replaced by vellus hair at about 33 to 36 weeks of gestational age. As the lanugo is shed from the skin, it is normal for the developing fetus to consume the hair with the fluid, since it drinks from the amniotic fluid and urinates it back into its environment. Subsequently, the lanugo contributes to the newborn baby's meconium. The presence of lanugo in newborns is a sign of premature birth.
It has been hypothesised that the lanugo of human fetuses aids in temperature regulation.[4]
Lanugo can be observed in malnourished patients, including those with eating disorders. When found along with other physical symptoms, for example, lanugo can help a physician make a diagnosis of anorexia nervosa.[5]
It is often found in teratomas (congenital tumours).
Lanugo is also common on other animals. For example, seals[6] and elephants[7][8][9] are often born with a covering of lanugo.
Fetal whales, like humans and all other primates, also have lanugo.
Look up lanugo in Wiktionary, the free dictionary. |
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リンク元 | 「100Cases 30」「毳毛」「pappus」「vellus」「fetal hair」 |
原発性無月経 | 続発性無月経 | |
視床下部性無月経 | カルマン症候群 | 視床下部の機能障害 |
フレーリヒ症候群 | 神経性食欲不振症 | |
Laurence-Moon-Biedl症候群 | 体重減少性無月経 | |
プラダ・ウィリ症候群 | 高プロラクチン血症 | |
Chiari-Frommel症候群 | ||
Argonz-del Castillo症候群 | ||
下垂体性無月経 | 先天性ゴナドトロピン欠損症 | シーハン症候群 |
empty sella症候群 | 下垂体腺腫 | |
Forbes-Albright症候群 | ||
卵巣性無月経 | 性腺形成不全 | 早発卵巣機能不全 |
ターナー症候群 | 多嚢胞性卵巣症候群 | |
卵巣摘出 | ||
卵巣の放射線障害 | ||
子宮性無月経 | ロキタンスキー・キュスター・ハウザー症候群 | アッシャーマン症候群 |
子宮奇形 | 子宮内膜炎 | |
処女膜閉鎖 | 子宮摘出術後 | |
膣性無月経 | 処女膜閉鎖症 | |
膣閉鎖症 | ||
その他 | 半陰陽(先天性副腎過形成、アンドロゲン不応症) | Cushing症候群 |
Addison病 | ||
Basedow病 | ||
甲状腺機能低下症 | ||
糖尿病 | ||
生理的 | 妊娠、産褥、授乳、閉経 |