uterus

uterus,

in most female mammals, hollow muscular organ in which the fetus develops and from which it is delivered at the end of pregnancypregnancy,
period of time between fertilization of the ovum (conception) and birth, during which mammals carry their developing young in the uterus (see embryo). The average duration of pregnancy in humans is about 280 days, equal to 9 calendar months.
..... Click the link for more information. . The human uterus is pear-shaped and about 3 in. (7.6 cm) long (it expands greatly during pregnancy); it normally lies in the pelvis, where it is supported by a ligament on either side extending to the pelvic wall. The body of the uterus tapers down to a necklike structure (cervix) that leads into the vagina. On either side of the uterus is an oviduct (called fallopian tube, or uterine tube, in humans) from 3 to 5 in. (7.6–12.7 cm) long, one end opening into the uterus and the other, wide-mouthed, ends in close proximity to an ovaryovary,
ductless gland of the female in which the ova (female reproductive cells) are produced. In vertebrate animals the ovary also secretes the sex hormones estrogen and progesterone, which control the development of the sexual organs and the secondary sexual characteristics.
..... Click the link for more information. . These oviducts serve as passageways for the ova to reach the uterus. Fertilization occurs in the oviduct; the fertilized ovum then continues into the uterus, where it becomes implanted in the lining of that organ, also known as the endometrium. If fertilization does not occur, the ovum and the lining of the uterine wall pass out of the body through the vagina (see menstruationmenstruation,
periodic flow of blood and cells from the lining of the uterus in humans and most other primates, occurring about every 28 days in women. Menstruation commences at puberty (usually between age 10 and 17).
..... Click the link for more information. ). Endometrial tissues then build up again in the uterus in anticipation of the next release of an ovum.

Diseases that can affect the uterus include various sexually transmitted diseasessexually transmitted disease
(STD) or venereal disease,
term for infections acquired mainly through sexual contact. Five diseases were traditionally known as venereal diseases: gonorrhea, syphilis, and the less common granuloma inguinale, lymphogranuloma venereum, and
..... Click the link for more information. , pelvic inflammatory diseasepelvic inflammatory disease
(PID), infection of the female reproductive organs, usually resulting from infection with the bacteria that cause chlamydia or gonorrhea. The infection typically first affects the cervical area, then spreads to the uterus, fallopian tubes, ovaries,
..... Click the link for more information. , and endometriosisendometriosis
, a condition in which small pieces of the endometrium (the lining of the uterus) migrate to other places in the pelvic area. The endometrial fragments may move to the fallopian tubes, ovaries, or other pelvic structures (e.g., the bladder or rectum).
..... Click the link for more information. , as well as benign or malignant tumors. Benign tumors may be removed without damage to the uterus, although in cases where the tissue is found to be cancerous, the entire uterus and cervix may have to be removed in a procedure known as hysterectomyhysterectomy
, surgical removal of the uterus. A hysterectomy may involve removal of the uterus only or additional removal of the cervix (base of the uterus), fallopian tubes (salpingectomy), and ovaries (oophorectomy).
..... Click the link for more information. . Prolapse of the uterus occurs when weakened supporting structures allow the uterus to tilt and slip downward into the vagina. See also reproductive systemreproductive system,
in animals, the anatomical organs concerned with production of offspring. In humans and other mammals the female reproductive system produces the female reproductive cells (the eggs, or ova) and contains an organ in which development of the fetus takes
..... Click the link for more information. .

Uterus

The hollow, muscular womb, being an enlarged portion of the oviduct in the adult female. An adult human uterus, before pregnancy, measures 3 × 2 × 1 in. (7.5 × 5 × 2.5 cm) in size and has the shape of an inverted, flattened pear. The paired Fallopian tubes enter the uterus at its upper corners; the lower, narrowed portion, the cervix, projects into the vagina (see illustration). Normally the uterus is tilted slightly forward and lies behind the urinary bladder.

Human uterus and associated structures

The lining, or mucosa, responds to hormonal stimulation, growing in thickness with a tremendous increase in blood vessels during the first part of the menstrual cycle. If fertilization does not occur, the thickened vascular lining is sloughed off, producing the menstrual flow at the end of the cycle, and a new menstrual cycle begins with growth of the mucosa. When pregnancy occurs, the mucosa continues to thicken and forms an intimate connection with the implanted and enlarging placenta. See Menstruation, Reproductive system

Uterus

in females a special, expanded section of the oviducts with a powerful muscular wall and a good supply of blood.

In animals. A uterus is found in annelids, arthropods, mollusks, most lower vertebrates (some cartilaginous and all viviparous bony fishes), certain amphibians, many reptiles, birds, and all mammals.

In oviparous vertebrates (reptiles and birds), the mature ova are held temporarily in the uterus. In viviparous animals, the embryonic development of the organism takes place there, using either the nutrients of the ovum or those of the mother. In the latter case, communication and the exchange of matter between the developing embryo and the uterus are accomplished through the placenta.

The structure of the uterus differs greatly from animal to animal. In Prototheria (duck-billed platypus, spiny anteater), the uterus is paired, and each uterus opens separately into a cloaca. In marsupials (kangaroo), the uterus is also paired, but each opens into a special vagina. In placental mammals, one finds all forms from paired uterus to unpaired.

Four main types of uterus are distinguished, depending on the degree of concrescence of the oviducts: uterus duplex, or two uteri, each opening independently into a common vagina (found in some rodents, elephants); uterus bipartitus, or two uteri, with the posterior sections grown together and opening by a common orifice into the vagina (in some rodents, ruminants, swine, carnivores); uterus bicornis, the most common in mammals, consisting of two uterine horns that join in the unpaired body of the uterus and opening into a vagina (in many carnivores, insectivores, cetaceans, artiodactyls, perissodactyls); and uterus simplex, consisting only of an unpaired body into which open two oviducts (in most chiropterans, primates, man).

REFERENCES

Kholodkovskii, N. A. Uchebnik zoologii, 6th ed. Moscow-Leningrad, 1933.
Kurs zoologii, 7th ed., vols. 1-2. Moscow, 1966.
Marshall’s Physiology of Reproduction, 3rd ed., 2 vols. Edited by A. S. Parkes. London-New York-Toronto, 1956-58.
Giersberg, H., and P. Rietschel. Vergleichende Anatomie der Wirbeltiere, vol. 2. Jena, 1968.

K. M. KURNOSOV

In man. In the female, the uterus is the fetus-bearing hollow muscular organ in the lesser pelvic cavity between the urinary bladder and the rectum.

The human uterus weighs 40-50 g in nulliparas and 90-100 g in multiparas. The organ is pear-shaped; the larger part is made up of the body (the upper part of which, called the fundus, is enlarged). The lower, narrowed end of the uterus (cervix) is held by the vagina. The cervix consists of two parts: the vaginal (facing the vagina) and the supravaginal. The fundus of the uterus inclines forward; the body and the cervix form an angle that opens forward. The cavity inside the uterus is triangular, with two upward openings leading to the fallopian tubes. The cavity of the uterus passes the cervical canal, which opens at the uterine ostium into the vagina.

The wall of the uterus consists of three membranes: outer (serous), middle (muscular), and inner (mucous). The serous membrane is represented by the peritoneum, which envelops the uterus from the front, rear, and sides and passes to the urinary bladder and the rectum, circumscribing the vesicouterine and rectouterine pouches. Along the sides of the uterus, the sheets of the peritoneum grow together to form the broad ligament of the uterus, which, together with the fascia and muscles of the pelvic floor, help to secure the organ.

The middle layer of the uterus is the most powerful, consisting of three layers of smooth muscle with added elastic fibers. The mucous membrane is lined with ciliated cylindrical epithelium and holds numerous glands. This layer undergoes changes in connection with the menstrual cycle.

Arterial blood is supplied to the uterus by branches of the uterine and ovarian arteries, which are especially well developed during pregnancy. Venous blood leaves the uterus through the uterine and ovarian veins; lymph, through efferent vessels to the aortoabdominal, hypogastric, and iliac lymph nodes. The uterus

Table 1. Output of principal products of the vegetable oil and fat industry in the USSR (thousands of tons)
	1913	1928	1940	1950	1960	1970	1972
Vegetable oil	538	448	798	819	1,586	2,784	2,842
Margarine	–	–	121	192	431	762	850
Mayonnaise	–	–	–	–	7.8	40.8	52.8
Soap (figured at 40-percent fatty-acid content)	192	311	700	816	1,451	1,442	1,223
Synthetic detergents	–	–	–	–	22.9	470	534
Natural drying oil	–	–	36.6	15	63.1	44.9	41.4
produced at enterprises of the Ministry of the Food Industry						15.6	16.8

is innervated by branches of the inferior mesenteric plexus and the pelvic nerves.

IA. L. KARAGANOV

uterus

[′yüd·ə·rəs] (anatomy) The organ of gestation in mammals which receives and retains the fertilized ovum, holds the fetus during development, and becomes the principal agent of its expulsion at term.

uterus

1. Anatomy a hollow muscular organ lying within the pelvic cavity of female mammals. It houses the developing fetus and by contractions aids in its expulsion at parturition 2. the corresponding organ in other animals

Uterus

uterus

[u´ter-us] (pl. u´teri) (L.) the hollow muscular organ in female mammals in which the zygote (fertilized ovum) normally becomes embedded and in which the developing embryo and fetus is nourished; in humans it is normally about the size and shape of a pear. Called also metra and womb.

The upper part of the uterus, or fundus uteri, is broad and flattened; the middle part (body), or corpus uteri, is large and open; and the lower part, or cervix uteri, is narrow and tubular and opens downward into the vagina. Two fallopian tubes enter the uterus at the upper end, one on each side. The walls of the uterus are composed of muscle, and its lining is mucous membrane. The muscular substance of the uterus is called the myometrium, and the inner lining is called the endometrium. Between puberty and menopause, the lining goes through a monthly cycle of growth and discharge, known as the menstrual cycle. menstruation" >menstruation is the time in the cycle when the tissue prepared by the uterus for a possible embryo or fertilized egg is unused and passes out through the vagina.
The menstrual cycle is interrupted by pregnancy when a mature ovum is fertilized by a spermatozoon. Fertilization usually takes place in the fallopian tube; the fertilized ovum continues moving along the tube and comes to rest in the uterus, where it implants in the endometrium. The endometrium then serves to anchor the placenta, which filters nutrients from the mother's blood into the blood of the growing fetus. (See also reproduction and female reproductive organs.)Disorders of the Uterus. The main organs of the female reproductive system, the uterus, fallopian tubes, and ovaries, are connected to each other by ligaments that normally hold each in its proper place. Occasionally childbirth causes displacement of the uterus. The ligaments may stretch and weaken enough to permit the uterus to bulge into the vagina. This is called a prolapsed uterus. The uterus is also subject to cancer as well as to benign growths in the uterine wall, called leiomyomas.

Uterus and uterine tubes. From Applegate, 2000.uterus didel´phys the existence of two distinct uteri in the same individual; called also didelphia and uterus duplex.duplex uterus (uterus du´plex) uterus didelphys.

u·ter·us

, pl.

u·ter·i

(yū'tĕr-ŭs, ū'ter-ī), [TA] The hollow muscular organ in which the ootid is developed into the embryo and fetus; it is about 7.5-cm long in a nonpregnant woman; consists of a main portion (body) with an elongated lower part (cervix), at the extremity of which is the opening (external os). The upper rounded portion of the uterus, opposite the os, is the fundus, at each extremity of which is the horn marking the part where the uterine tube joins the uterus and through which the morula reaches the uterine cavity after leaving the uterine tube. The organ is passively supported in the pelvic cavity by the vagina and paracolpium and by the anteflexion and anteversion of the normal uterus, which places its mass superior to the bladder; it is actively supported by the tonic and phasic contraction of the muscles of the pelvic floor. Synonym(s): metra, womb [L.]

uterus

(yo͞o′tər-əs)n. pl. uteri (yo͞o′tə-rī′) or uteruses 1. A hollow muscular organ located in the pelvic cavity of female mammals in which the fertilized egg implants and develops. Also called womb.2. A corresponding part in other animals.

u·ter·us

, pl. uteri (yū'tĕr-ŭs, -ī) [TA] The hollow muscular organ in which the blastocyst develops into a fetus; it consists of a main portion (body) with an elongated lower part (cervix), at the extremity of which is the opening (os). The upper rounded portion of the uterus, opposite the os, is the fundus, at each extremity of which is the horn marking the part where the uterine tube joins the uterus and through which the morula reaches the uterine cavity after leaving the uterine tube. The organ is supported in the pelvic cavity by the broad ligaments, round ligaments, cardinal ligaments, and rectouterine and vesicouterine folds or ligaments.
Synonym(s): metra, womb. [L.]

uterus

(ut'e-rus) [L. uterus, womb]

UTERUS: Uterus and its ligaments seen laparoscopically (×1/3)The reproductive organ for containing and nourishing the embryo and fetus from the time the fertilized egg is implanted to when the fetus is born. Synonym: womb See: illustration; genitalia, female for illus.

Anatomy

The uterus is a muscular, hollow, pear-shaped organ situated in the midpelvis between the sacrum and the pubic symphysis. Before child-bearing, it is about 3 in. (7.5 cm) long, 2 in. (5 cm) wide, and 1 in. ( 2.5 cm) thick. Its upper surface is covered by the perimetrium, and it is supported by the pelvic diaphragm supplemented by the two broad ligaments, two round ligaments, and two uterosacral ligaments. It is usually tilted forward over the top of the urinary bladder. The upper portion of the uterus, between the openings of the fallopian tubes, is the fundus; the large central portion is the body; and the narrow lower end is the cervix, which projects into the vagina. The cavity of the uterus is widest in the fundus. The canal of the cervix is narrow, opens into the uterine cavity at the internal os, and into the vagina at the external os.

The wall of the uterus consists of the outer perimetrium, middle myometrium, and inner endometrium. The uterine and ovarian arteries supply blood to the uterus.

Positions

Anteflexion: The uterus bends forward. Anteversion: The fundus is displaced forward toward the pubis, while the cervix is tilted up toward the sacrum. Retroflexion: The uterus bends backward at the junction of the body and the cervix. Retroversion: The uterus inclines backward with retention of the normal curve; this position is the opposite of anteversion.

See: hysterectomy; pregnancy

uterus acollis

A uterus without a cervix.

uterus arcuatus

A uterus with a depressed arched fundus.

uterus bicornis

A uterus in which the fundus is divided into two parts.

uterus biforis

A uterus in which the external os is divided into two parts by a septum.

uterus bilocularis

A uterus in which the cavity is divided into two parts by a partition.

bipartite uterus

A uterus in which the body is partially divided by a median septum.

uterus cordiformis

A heart-shaped uterus.

Couvelaire uterus

See: Couvelaire uterus

uterus didelphys

Double uterus.

double uterus

A congenital anomaly in which abnormalities in the formation of the müllerian ducts result in a duplication of the uterus, a uterus with a divided cavity, or sometimes, two copies of the cervix or vagina. Synonym: dimetria; uterus didelphys

uterus duplex

A double uterus resulting from failure of union of müllerian ducts.

fetal uterus

A uterus that is retarded in development and possesses an extremely long cervical canal.

gravid uterus

A pregnant uterus.

host uterus

The uterus of a woman who serves as a surrogate mother for a couple who want their fertilized egg carried to term.

uterus masculinus

The prostatic utricle.

uterus parvicollis

A normal uterus with a disproportionately small cervix.

pubescent uterus

An adult uterus that resembles that of a prepubertal female.

tipped uterus

Malposition of the uterus, and for symptoms thought to arise from that condition..

uterus unicornis

A uterus possessing only one lateral half and usually having only one uterine tube. About 20% to 30% of women who have this structural abnormality also experience repeated spontaneous abortion during early pregnancy.

uterus

The female organ in which the fetus grows and is nourished until birth. The uterus is a hollow, muscular organ, about 8 cm long in the non-pregnant state, situated at the upper end of the VAGINA and lying behind and above the URINARY BLADDER and in front of the RECTUM. It is suspended by LIGAMENTS from the walls of the pelvis. The lining of the uterus is called the endometrium. Under the influence of hormones from the ovaries this thickens progressively until shed during menstruation. In pregnancy, the uterus expands considerably with the growth of the fetus until it rises almost to the top of the abdominal cavity.

uterus

the enlarged posterior portion of the OVIDUCT in which the embryo implants and develops in VIVIPAROUS (1) species. The human uterus is also called the womb.

Uterus

A muscular, hollow organ of the female reproductive tract. The uterus contains and nourishes the embryo and fetus from the time the fertilized egg is implanted until birth.Mentioned in: Antihemorrhoid Drugs, Choriocarcinoma, Dysmenorrhea, Ehlers-Danlos Syndrome, Endometrial Biopsy, Hormone Replacement Therapy, Menopause, Oral Contraceptives, Placental Abruption, Preeclampsia and Eclampsia

Patient discussion about Uterus

Q. Is it safe to have sex with a woman with cancer of the uterus? My 45-years old wife was told she have cancer in the uterus, and will have an operation soon. Meanwhile, should we use a condom during sex? Can the tumor pass from her to me (like AIDS or HPV)?A. unless the cancer has lots of bleeding, you don't need to use condoms.
but if your wife would undergo an operation, maybe you need to be off-of-that-sex 1-2 days prior to operation day, just to make sure there's no super infection that will bother the operation plan.

Q. I had my uterus removed in 2000, what exercises are effective for firming the flab that we women deal with? exercises to firm muscles of tummy after uterus is removedA. pelvic muscles exercise is very important in order to avoid unpleasant situations and procedures. i once had the pleasure of seeing a surgery done in order to fix a complication of weak pelvic muscles.
not a very nice surgery.
here are some sites that give nice exercises:
http://familydoctor.org/online/famdocen/home/women/reproductive/gynecologic/642.html
http://www.seekwellness.com/incontinence/how_to_do_pelvic_muscle_exercise.htm

Q. Can the fetus hear through the womb? My wife wants to play music to our baby and put earphones on her pregnant stomach so he can hear it. Can he really hear the music?A. Yes, he can hear. Studies show that from the 5th month of pregnancy, nice and calm music can sooth the fetus. You can expose your baby to sounds, music and different tunes throughout your pregnancy.

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REFERENCES

uterus

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Anatomy

Positions

uterus acollis

uterus arcuatus

uterus bicornis

uterus biforis

uterus bilocularis

bipartite uterus

uterus cordiformis

Couvelaire uterus

uterus didelphys

double uterus

uterus duplex

fetal uterus

gravid uterus

host uterus

uterus masculinus

uterus parvicollis

pubescent uterus

tipped uterus

uterus unicornis

uterus

uterus

Uterus

Patient discussion about Uterus

uterus

Synonyms for uterus

noun a hollow muscular organ in the pelvic cavity of females

Synonyms

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