Uterus
Tue . 18 Aug 2018

Uterus

uterus, uterus anatomy
The uterus from Latin "uterus", plural uteri or womb is a major female hormone-responsive reproductive sex organ of most mammals, including humans One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, uterine tubes depending on the species It is within the uterus that the fetus develops during gestation, usually developing completely in placental mammals such as humans and partially in marsupials such as kangaroos and opossums Two uteri usually form initially in a female and usually male fetus, and in placental mammals they may partially or completely fuse into a single uterus depending on the species In many species with two uteri, only one is functional Humans and other higher primates such as chimpanzees, usually have a single completely fused uterus, although in some individuals the uteri may not have completely fused Horses, on the other hand, have bipartite uteri In English, the term uterus is used consistently within the medical and related professions, while the Germanic-derived term womb is more common in everyday usage

Most animals that lay eggs, such as birds and reptiles, including most ovoviviparous species, have an oviduct instead of a uterus Note however, that recent research into the biology of the viviparous not merely ovoviviparous skink Trachylepis ivensi has revealed development of a very close analogue to eutherian mammalian placental development

In monotremes, mammals which lay eggs, namely the platypus and the echidnas, either the term uterus or oviduct is used to describe the same organ, but the egg does not develop a placenta within the mother and thus does not receive further nourishment after formation and fertilization

Marsupials have two uteri, each of which connect to a lateral vagina and which both use a third, middle "vagina" which functions as the birth canal Marsupial embryos form a choriovitelline "placenta" which can be thought of as something between a monotreme egg and a "true" placenta, in which the egg's yolk sac supplies a large part of the embryo's nutrition but also attaches to the uterine wall and takes nutrients from the mother's bloodstream

Contents

  • 1 Structure
    • 11 Regions
    • 12 Layers
    • 13 Support
    • 14 Axes
      • 141 Major ligaments
    • 15 Position
    • 16 Shape
    • 17 Blood supply
    • 18 Nerve supply
    • 19 Histology
    • 110 Development
  • 2 Function
  • 3 Diseases of the uterus
  • 4 Uterus transplantation
  • 5 Additional images
  • 6 See also
  • 7 References
  • 8 External links

Structure

The uterus is located inside the pelvis immediately dorsal and usually somewhat rostral to the urinary bladder and ventral to the rectum The human uterus is pear-shaped and about 3 in 76 cm long, 45 cm broad side to side and 30 cm thick anteroposterior A typical adult uterus weighs about 60 grams The uterus 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:

  • Cervix uteri – "neck of uterus"
    • External orifice of the uterus
    • Canal of the cervix
    • Internal orifice of the uterus
  • corpus uteri – "Body of uterus"
    • Cavity of the body of the uterus
    • Fundus uterus

Layers

The three layers, from innermost to outermost, are as follows:

Endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus It has a basal layer and a functional layer; the functional layer thickens and then is sloughed during the menstural cycle or estrous cycle During pregnancy, the glands and blood vessels in the endometrium further increase in size and number Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus As of 2015 only preliminary studies had been made of human microbiota colonizing the endometrium; they were too small too allow generalizations to be drawn 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 Serous layer of visceral peritonium It covers the outer surface of the uterus

Support

The uterus is primarily supported by the pelvic diaphragm, perineal body and the urogenital diaphragm Secondarily, it is supported by ligaments and the peritoneum broad ligament of uterus

Axes

Normally the uterus lies in anteversion & anteflexion In most women, the long axis of the uterus is bent forward on the long axis of the vagina, against the urinary bladder This position is referred to as anteversion of the uterus Furthermore, the long axis of the body of the uterus is bent forward at the level of the internal os with the long axis of the cervix This position is termed anteflexion of the uterus Uterus assumes anteverted position in 50% women, retroverted position in 25% women and rest have midposed 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:

Name From To
Uterosacral ligament Posterior cervix Anterior face of sacrum
Cardinal ligaments Side of the cervix Ischial spines
Pubocervical ligament Side of the cervix Pubic symphysis

Position

The uterus is in the middle of the pelvic cavity in frontal plane due to ligamentum latum uteri The fundus does not surpass the linea terminalis, while the vaginal part of the cervix does not extend below interspinal line The uterus is mobile and moves posteriorly under the pressure of a full bladder, or anteriorly under the pressure of a full rectum If both are full, it moves upwards Increased intraabdominal pressure pushes it downwards The mobility is conferred to it by musculo-fibrous apparatus that consists of suspensory and sustentacular part Under normal circumstances the suspensory part keeps the uterus in anteflexion and anteversion in 90% of women and keeps it "floating" in the pelvis 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": Fundus is pointing forward relative to the cervix "Retroflexed": Fundus is pointing backwards

Sustentacular part supports the pelvic organs and comprises the larger pelvic diaphragm in the back and the smaller urogenital diaphragm in the front

The pathological changes of the position of the uterus are:

  • retroversion/retroflexion, if it is fixed
  • hyperanteflexion – tipped too forward; most commonly congenital, but may be caused by tumors
  • anteposition, retroposition, lateroposition – the whole uterus is moved; caused by parametritis or tumors
  • elevation, descensus, prolapse
  • rotation the whole uterus rotates around its longitudinal axis, torsion only the body of the uterus rotates around
  • inversion

In cases where the uterus is "tipped", also known as retroverted uterus, women may have symptoms of pain during sexual intercourse, pelvic pain during menstruation, minor incontinence, urinary tract infections, fertility difficulties, and difficulty using tampons A pelvic examination by a doctor can determine if a uterus is tipped

Shape

In mammals, the four main forms in which it is found are:

Duplex   There are two wholly separate uteri, with one fallopian tube each Found in marsupials such as kangaroos, Tasmanian devils, opossums, etc, rodents such as mice, rats, and guinea pigs, and lagomorpha rabbits and hares Bipartite   The two uteri are separate for most of their length, but share a single cervix Found in ruminants deer, moose, elk etc, hyraxes, cats, and horses Bicornuate  The upper parts of the uterus remain separate, but the lower parts are fused into a single structure Found in dogs, pigs, elephants, whales, dolphins, and tarsiers, and strepsirrhine primates among others Simplex   The entire uterus is fused into a single organ Found in higher primates including humans and chimpanzees Occasionally, some individual females including humans may have a bicornuate uterus, a uterine malformation where the two parts of the uterus fail to fuse completely during fetal development

In monotremes such as the platypus, the uterus is duplex and rather than nurturing the embryo, secretes the shell around the egg It is essentially identical with the shell gland of birds and reptiles, with which the uterus is homologous

Blood supply

Vessels of the uterus and its appendages, rear view Schematic diagram of uterine arterial vasculature seen as a cross-section through the myometrium and endometrium

The uterus is supplied by arterial blood both from the uterine artery and the ovarian artery Another anastomotic branch may also supply the uterus from anastomosis of these two arteries

Nerve supply

Afferent nerves supplying uterus are T11 and T12 Sympathetic supply is from hypogastric plexus and ovarian plexus Parasympathetic supply is from second, third and fourth sacral nerves

Histology

Development

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

Function

The uterus consists of a body and a cervix The cervix protrudes into the vagina The uterus is held in position within the pelvis by condensations of endopelvic fascia, which are called ligaments These ligaments include the pubocervical, transverse cervical ligaments or Mackenrodt's ligaments or cardinal ligaments, and the uterosacral ligaments It is covered by a sheet-like fold of peritoneum, the broad ligament

The uterus is essential in sexual response by directing blood flow to the pelvis and ovaries, and to the external genitals, including the vagina, labia, and clitoris

The reproductive function of the uterus is to accept a fertilized ovum which passes through the utero-tubal junction from the fallopian tube uterine tube It implants into the endometrium, and derives nourishment from blood vessels which develop exclusively for this purpose The fertilized ovum becomes an embryo, attaches to a wall of the uterus, creates a placenta, and develops into a fetus 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 22 pounds

Diseases of the uterus

Some pathological states include:

  • Prolapse of the uterus
  • Carcinoma of the cervix – malignant neoplasm
  • Carcinoma of the uterus – malignant neoplasm
  • Fibroids – benign neoplasms
  • Adenomyosis – ectopic growth of endometrial tissue within the myometrium
  • Endometritis, infection at the uterine cavity
  • Pyometra – infection of the uterus, most commonly seen in dogs
  • Uterine malformations mainly congenital malformations including Uterine Didelphys, bicornuate uterus and septate uterus It also includes congenital absence of the uterus Rokitansky syndrome
  • Asherman's syndrome, also known as intrauterine adhesions occurs when the basal layer of the endometrium is damaged by instrumentation eg D&C or infection eg endometrial tuberculosis resulting in endometrial scarring followed by adhesion formation which partially or completely obliterates the uterine cavity
  • Hematometra, which is accumulation of blood within the uterus
Transvaginal ultrasonography showing a uterine fluid accumulation in a postmenopausal woman
  • Accumulation of fluids other than blood or of unknown constitution One study came to the conclusion that postmenopausal women with endometrial fluid collection on gynecologic ultrasonography should undergo endometrial biopsy if the endometrial lining is thicker than 3 mm or the endometrial fluid is echogenic In cases of a lining 3 mm or less and clear endometrial fluid, endometrial biopsy was not regarded to be necessary, but endocervical sampling to rule out endocervical cancer was recommended
  • Myometritis, an infection of the uterine muscular layer

Uterus transplantation

In 2012, the world's first womb transplant from a dead donor was performed on a Turkish woman who was born without a womb, but has her own ovaries She is in good condition and the womb is functional In the year 2000 in Saudi Arabia a similar transplant was performed, but from a live donor Although womb transplants have been successful in animals such as mice, rats and sheep, the prevailing opinion in the field is that the risks are too great Apart from risks of rejection of the new womb, there is concern that the drugs necessary for prevention of rejection of the donated womb might harm the fetus

Additional images

See also

  • Ovule
  • Hysterectomy
  • Menopause
  • Uterine glands
  • Artificial uterus
  • Retroverted uterus
  • Social uterus

References

  1. ^ Blackburn, D G; Flemming, A F 2011 "Invasive implantation and intimate placental associations in a placentotrophic African lizard, Trachylepis ivensi scincidae" Journal of Morphology 273: 137–59 doi:101002/jmor11011 PMID 21956253 
  2. ^ a b Manual of Obstetrics 3rd ed Elsevier 2011 pp 1–16 ISBN 9788131225561
  3. ^ Blue Histology - Female Reproductive System School of Anatomy and Human Biology - The University of Western Australia Accessed 20061228 20:35
  4. ^ Guyton AC and Hall JE, eds 2006 "Chapter 81 Female Physiology Before Pregnancy and Female Hormones" Textbook of Medical Physiology 11th ed Elsevier Saunders pp 1018ff ISBN 9780721602400  CS1 maint: Uses editors parameter link
  5. ^ Franasiak, Jason M; Scott, Richard T 2015 "Reproductive tract microbiome in assisted reproductive technologies" Fertility and Sterility 104 6: 1364–1371 doi:101016/jfertnstert201510012 ISSN 0015-0282 PMID 26597628 
  6. ^ Ross, Michael H; Pawlina, Wojciech Histology, a text and atlas Sixth ed p 848 
  7. ^ a b The Pelvis University College Cork Archived from the original on 2008-02-27
  8. ^ Snell, Clinical Anatomy by regions, 8th edition
  9. ^ http://wwwwomens-healthcouk/retroverasp
  10. ^ Tipped Uterus:Tilted Uterus AmericanPregnancyorg Accessed 25 March 2011
  11. ^ Romer, Alfred Sherwood; Parsons, Thomas S 1977 The Vertebrate Body Philadelphia, Pennsylvania: Holt-Saunders International pp 390–392 ISBN 0-03-910284-X 
  12. ^ Gray's Anatomy for Students, 2nd edition
  13. ^ Takacs P, De Santis T, Nicholas MC, Verma U, Strassberg R, Duthely L November 2005 "Echogenic endometrial fluid collection in postmenopausal women is a significant risk factor for disease" J Ultrasound Med 24 11: 1477–81 PMID 16239648 
  14. ^ "The world's first womb transplant: Landmark surgery brings hope to millions of childless women – and it could be in Britain soon" May 25, 2012 

External links

  • Gray's s268
  • Anatomy photo:43:01-0102 at the SUNY Downstate Medical Center – "The Female Pelvis: Organs in the Female and male Pelvis in situ"
  • Encyclopediacom
  • Uterus Anatomy
  • Uterus Pregnancy

uterus, uterus anatomy, uterus biopsy, uterus didelphys, uterus fibroids, uterus infection, uterus pain, uterus problems, uterus prolapse, uterus removal


Uterus Information about

Uterus


  • user icon

    Uterus beatiful post thanks!

    29.10.2014


Uterus
Uterus
Uterus viewing the topic.
Uterus what, Uterus who, Uterus explanation

There are excerpts from wikipedia on this article and video

Random Posts

Body politic

Body politic

The body politic is a metaphor that regards a nation as a corporate entity,2 likened to a human body...
Kakamega

Kakamega

Kakamega is a town in western Kenya lying about 30 km north of the Equator It is the headquarte...
Academic year

Academic year

An academic year is a period of time which schools, colleges and universities use to measure a quant...
Lucrezia Borgia

Lucrezia Borgia

Lucrezia Borgia Italian pronunciation: luˈkrɛttsja ˈbɔrdʒa; Valencian: Lucrècia Borja luˈkrɛsia...