Everything about Womb totally explained
The
uterus (from the Latin word for
womb) is the major
female reproductive
organ of most
mammals, including
humans. One end, the
cervix, opens into the
vagina; the other is connected on both sides to the
Fallopian tubes. The term
uterus is commonly used within the medical and related professions, whilst
womb is in more common usage. The plural of uterus is uteruses or uteri.
Function
The main function of the uterus is to accept a fertilized
ovum which becomes implanted into the
endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose. The fertilized ovum becomes an
embryo, develops into a
fetus and gestates until
childbirth. Due to anatomical barriers such as the
pelvis, the uterus is pushed partially into the abdomen due to its expansion during pregnancy. Even during pregnancy the mass of a human uterus amounts to only about a kilogram (2.2 pounds).
Forms in mammals
In mammals, the four main forms in which it's found are:
Bipartite : Found in ruminants (cattle, goats, sheep, camels, llamas, giraffes, bison, buffalo, deer, etc.).
; Bicornuate : Found in pigs, cats, and dogs.
Simplex : Found in humans, other primates and horses.
; Duplex : Found in rodents (such as mice, rats and guinea pigs), marsupials and lagomorpha (rabbits and hares).
Anatomy
The uterus is located inside the
pelvis immediately
dorsal (and usually somewhat
rostral) to the
urinary bladder and
ventral to the
rectum. Outside of
pregnancy, its size in humans is several
centimeters in diameter. The uterus is a pear shaped muslcular organ which can be divided anatomically into four segments: The fundus, corpus, cervix and the internal os.
Regions
From outside to inside, the path to the uterus is as follows:
Layers
The layers, from innermost to outermost, are as follows:
Endometrium : The lining of the uterine cavity is called the "endometrium." In most mammals, including humans, the endometrium builds a lining periodically which, if no pregnancy occurs, is shed or reabsorbed. Shedding of the endometrial lining in humans is responsible for menstrual bleeding (known colloquially as a woman's "period") throughout the fertile years of a female and for some time beyond. In other mammals there may be cycles set as widely apart as six months or as frequently as a few days.
; Myometrium : The uterus mostly consists of smooth muscle, known as "myometrium." The innermost layer of myometrium is known as the junctional zone, which becomes thickened in adenomyosis.
Perimetrium : The loose surrounding tissue is called the "perimetrium."
; Peritoneum : The uterus is surrounded by "peritoneum."
Support
The uterus is primarily supported by the
pelvic diaphragm and the
urogenital diaphragm. Secondarily, it's supported by ligaments and the peritoneum (
broad ligament of uterus)
Major ligaments
It is held in place by several
peritoneal ligaments, of which the following are the most important (there are two of each):
Other named ligaments near the uterus, for example the broad ligament, the round ligament, the suspensory ligament of the ovary, the infundibulopelvic ligament, have no role in the support of the uterus.
Position
Under normal circumstances the uterus is both "anteflexed" and "anteverted." The meaning of these terms are described below:
| Distinction |
More common |
Less common |
| Position tipped |
"anteverted": tipped forward |
"retroverted": tipped backwards |
| Position of fundus |
"anteflexed": the fundus is pointing forward relative to the cervix |
"retroflexed": the fundus is pointing backwards |
Development
The bilateral
Müllerian ducts form during early fetal life. In males,
MIF secreted from the testes leads to their regression. In females these ducts give rise to the
Fallopian tubes and the uterus. In humans the lower segments of the two ducts fuse to form a single uterus, however, in cases of
uterine malformations this development may be disturbed. The different uterine forms in various mammals are due to various degrees of fusion of the two Müllerian ducts.
Pathology
Some
pathological states include:
Prolapse of the uterus
Carcinoma of the cervix – malignant neoplasm
Carcinoma of the uterus – malignant neoplasm
Ectopic pregnancy
Fibroids – benign neoplasms
Adenomyosis – ectopic growth of endometrial tissue within the myometrium
Pyometra – infection of the uterus, most commonly seen in dogs
Uterine malformation
Uterine Didelphys – split or doubled vagina/uterus
Retroverted uterus
Rokitansky syndrome
Myoma
Additional images
Image:Scheme_female_reproductive_system-en.svg|Schematic frontal view of female anatomy
Image:Illu cervix.jpg|Uterus and uterine tubes.
Image:Illu icd o codes.jpg
Image:PregnancyAnatomicalModel.jpg|Anatomical model of a human pregnancy
Image:Gray34.png|Sectional plan of the gravid uterus in the third and fourth month.
Image:Gray38.png|Fetus in utero, between fifth and sixth months.
Image:Gray589.png|Vessels of the uterus and its appendages, rear view.
Image:Gray1161.png|Uterus and right broad ligament, seen from behind.
Image:Gray1165.png|Female pelvis and its contents, seen from above and in front.
Image:Gray1166.png|Sagittal section of the lower part of a female trunk, right segment.
Image:Gray1167.svg|Posterior half of uterus and upper part of vagina.
Image:Gray1170.png|The arteries of the internal organs of generation of the female, seen from behind.
Image:Gray1230.png|Median sagittal section of female pelvis.
Further Information
Get more info on 'Womb'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://uterus.totallyexplained.com">Uterus Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
