{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
neutral
عضو رائد
المشاركات: 5,786
الانضمام: Mar 2004
|
سؤال يتعلق بجماعة الجنس الثالث .
مقال جيد ومبسط للموضوع بويكيبيديا وبه توضيح أكثر لبعض العك الذي ذكرته
http://en.wikipedia.org/wiki/Intersex
تعريف للحالة وتوضيح للتعارض بين الجينات والظاهر
Arrayconditions in which chromosomal sex is inconsistent with phenotypic
sex, or in which the phenotype is not classifiable as either male or female[/quote]
ArrayIncongruence between chromosomal and phenotypic sex
The final body appearance doesn't always correspond with what is dictated by the genes. In other words, there is sometimes an incongruence between genotypic (chromosomal) and phenotypic sex. Although there neither no less common chromosomal sex nor mosaicism/chimerism, but just the most common types (XY or XX), less common phenotypes still appear in such cases. In this sense, the common habit in the 21st century of elevating the role of the sex chromosomes above all other factors when determining gender may be analogous to the older habit of finding "true" sex in the gonads.
This phenomenon complicates the common XY sex-determination system, because it proves that genes don't always definitely determine the sex.[24][/quote]
ذكر لأهم أسباب الحالة وهما عيب بالsuprarenal gland أو عدم حساسية للهرمون ( مثال التلفزيون)
ArrayThe cause of such an incongruence is mostly congenital adrenal hyperplasia, where the kidney synthesizes vitilizing hormones, even in the absence of testes. Another cause is androgen insensitivity syndrome, where testes are present and functional, but the body doesn't respond properly to them. In either the case of AIS or CAH, testing of the chromosomes can be done to determine the genetic sex of the individual. Both are described below:[/quote]
ArrayCongenital adrenal hyperplasia
Main article: Congenital adrenal hyperplasia
The most common cause of sexual ambiguity is congenital adrenal hyperplasia (CAH), an endocrine disorder in which the adrenal glands produce abnormally high levels of virilizing hormones. In genetic females, this leads to an appearance that may be slightly masculinized (large clitoris) to quite masculine.
[edit] Cause
CAH is a genetic disorder in which the adrenal glands, while trying to make cortisone, may make an unusually high level of masculinizing hormones. When CAH occurs in an XY embryo, this is not an intersex condition, because it rather enhances the masculine characteristics.
Due to a defect in one of the enzymes that synthesize adrenal hormones, a blockage in one synthetic pathway will occur, هو ده العك بتاع مادة Aو M و F وإنزيم X و Y بس بأسلوب محترمcausing excessive production of androgenic hormones in a different pathway, virilizing an XX fetus in utero. Genitalia may appear completely masculine, or it may be ambiguous.[17].
In persistent müllerian duct syndrome, the child has XY chromosomes typical of a male. The child has a male body and an internal uterus and fallopian tubes because his body did not produce Müllerian inhibiting factor during fetal development.
A similar phenomenon occurs in cases where a cow brings two fraternal twins, one male and one female, to term. Because (unlike humans) such twins share hormones via their placental blood interface with the mother cow, male hormones produced in the body of the fetal bull find their way into the body of the fetal cow and masculinize her brain. The result is a freemartin (unconventional heifer), a cow that will eventually try to mount other cows the way that a bull would. [/quote]
ده مثال التلفزيون
ArrayAndrogen insensitivity syndrome
Main article: Androgen insensitivity syndrome
People with AIS have typically male chromosomes (XY), along with typically female appearance and genitalia.
Although people with AIS have a vagina, they lack a uterus, cervix of the uterus, and ovaries, and are thereby infertile. The vagina may be shorter than average; in some cases it is nearly absent. Instead of female internal reproductive organs, a person with AIS has undescended or partially descended testes, of which she may not even be aware.
AIS may be called the genetic male's equivalent of CAH, since AIS affects people with XY genotype, while CAH affects people with XX genotype.[/quote]
لسه مش فاهم , مش مشكلتي وأنا غلطان إني رديت عليك
|
|
| 08-09-2007, 01:17 AM |
|
{myadvertisements[zone_3]}
{myadvertisements[zone_3]}
|
بحث
قائمة الأعضاء
التقويم
وثائق المساعدة
/
سؤال يتعلق بجماعة الجنس الثالث .
