| Endometrium | |
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| Uterus and uterine tubes. (Endometrium labeled at center right. ) | |
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| Opened uterus with cat fetus in midgestation: 1 umbilicus, 2 amnion, 3 allantois, 4 Yolk sac, 5 developing marginal hematoma, 6 maternal part of placenta (endometrium) | |
| Latin | tunica mucosa uteri |
| Gray's | subject #268 1262 |
| MeSH | Endometrium |
| Dorlands/Elsevier | t_22/12832078 |
The endometrium is the inner membrane of the mammalian uterus. WikipediaManual of Style (spelling, articles should conform to one overall spelling style of English typically the one most linked to the article topic (if it is geographic For the alien race in Stephen Donaldson 's The Gap Cycle, see Amnion (Gap Cycle. Allantois (plural allantoides or allantoises) is a part of a developing animal Conceptus (which consists of all Embryonic and extra-embryonic The yolk sac is the first element seen in the Gestational sac during Pregnancy, usually at 5 weeks Gestation. A hematoma, or haematoma, is a collection of Blood outside the blood vessels generally the result of Hemorrhage, or more specifically Internal bleeding The placenta is an Ephemeral organ present in placental Vertebrates, such as Eutherial Mammals and Sharks during Gestation Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Gray's Anatomy the Respiratory apparatus ( Apparatus Respiratorius Respiratory system Respiratory apparatus Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands The uterus (from the Latin word for womb) is the major Female reproductive organ of most Mammals including Humans One end the
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Function
The endometrium functions as a lining for the uterus, preventing adhesions between the opposed walls of the myometrium, thereby maintaining the patency of the uterine cavity. The myometrium is the middle layer of the uterine wall consisting of smooth muscle cells and supporting stromal and vascular tissue During the menstrual cycle or estrous cycle, the endometrium grows to a thick, blood vessel-rich, glandular tissue layer. The menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive-age Females Overt menstruation (where there is blood flow from the Oestrus is also the biological genus name of the gadfly. The estrous cycle (also oestrous cycle; derived from Latin This represents an optimal environment for the implantation of a blastocyst upon its arrival in the uterus. Implantation is an event that occurs early in pregnancy in which the Embryo adheres to the wall of Uterus. The blastocyst is the structure formed in early Embryogenesis, after the formation of the Blastocoel, but before Implantation.
During pregnancy, the glands and blood vessels in the endometrium further increase in size and number. Pregnancy ( Latin graviditas) is the carrying of one or more offspring known as a Fetus or Embryo, inside the Uterus of a Female The blood vessels are part of the Circulatory system and function to transport Blood throughout the body Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus. The placenta is an Ephemeral organ present in placental Vertebrates, such as Eutherial Mammals and Sharks during Gestation Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular A fetus (or foetus or fœtus) is a developing Mammal or other Viviparous Vertebrate, after the Embryonic stage and
Cycle
The endometrial lining undergoes cyclic regeneration. Humans and the great apes display the menstrual cycle, whereas most other mammals are subject to an estrous cycle. The menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive-age Females Overt menstruation (where there is blood flow from the Oestrus is also the biological genus name of the gadfly. The estrous cycle (also oestrous cycle; derived from Latin In both cases, the endometrium initially proliferates under the influence of estrogen. Estrogens (US otherwise oestrogens or œstrogens) are a group of Steroid compounds named for their importance in the Estrous cycle, However, once ovulation occurs, in addition to estrogen, the ovary will also start to produce progesterone. Note This article deals primarily with Human ovulation nonhuman Animal ovulation is touched on briefly at the conclusion Progesterone is a C-21 Steroid Hormone involved in the Female Menstrual cycle, Pregnancy (supports Gestation This changes the proliferative pattern of the endometrium to a secretory lining. Eventually, the secretory lining provides a hospitable environment for one or more blastocysts.
If no blastocyst is detected, the progesterone level drops and the endometrial lining is either reabsorbed (estrous cycle) or shed (menstrual cycle). In the latter case, the process of shedding involves the breaking down of the lining, the tearing of small connective blood vessels, and the loss of the tissue and blood that had constituted it through the vagina. The vagina (from Latin, literally " Sheath " or " Scabbard " is a fibromuscular tubular tract leading from the Uterus The entire process occurs over a period of several days. Menstruation may be accompanied by a series of uterine contractions; These help expel the menstrual endometrium.
In case of implantation, however, the endometrial lining is neither absorbed nor shed. Instead, it remains as decidua. Decidua is the term for the uterine lining ( Endometrium) during a Pregnancy, which forms the maternal part of the placenta The decidua becomes part of the placenta; it provides support and protection for the gestation.
If there is inadequate stimulation of the lining, due to lack of hormones, the endometrium remains thin and inactive. In humans, this will result in amenorrhea. Amenorrhoea ( BE) amenorrhea ( AmE) or amenorrhœa, is the absence of a Menstrual period in a woman of reproductive age After menopause, the lining is often described as being atrophic. Menopause is the permanent shutting down of the female Reproductive system, a considerable length of time before the end of the lifespan In contrast, endometrium that is chronically exposed to estrogens, but not to progesterone, may become hyperplastic.
In humans, the cycle of building and shedding the endometrial lining lasts an average of 28 days. The endometrium develops at different rates in different mammals. Its formation is sometimes affected by seasons, climate, stress, and other factors. The endometrium itself produces certain hormones at different points along the cycle. Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body This affects other portions of the reproductive system. The reproductive system is a system of organs within an Organism which work together for the purpose of Reproduction.
Histology
The endometrium consists of a single layer of columnar epithelium, resting on a layer of connective tissue, which varies in thickness according to hormonal influences - the stroma. Columnar epithelia are epithelial cells whose heights are at least four times their width Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, Muscle, and Nervous tissue) Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Simple tubular uterine glands reach from the endometrial surface through to the base of the stroma, which also carries a rich blood supply of spiral arteries. A gland is an organ in an animal's body that synthesizes a substance for release such as Hormones or Breast milk, often into the Bloodstream The helicine branches of uterine artery (or helicine arterioles, or spiral arteries) are small arteries which temporarily supply the Endometrium of the In a woman of reproductive age, two layers of endometrium can be distinguished. These two layers occur only in endometrium lining the cavity of the uterus, not in the lining of the Fallopian tubes:[1]
- The functional layer is adjacent to the uterine cavity. This layer is built up after the end of menstruation during the first part of the previous menstrual cycle. The menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive-age Females Overt menstruation (where there is blood flow from the Proliferation is induced by estrogen (follicular phase of menstrual cycle), and later changes in this layer are engendered by progestrone from the corpus luteum (luteal phase). Estrogens (US otherwise oestrogens or œstrogens) are a group of Steroid compounds named for their importance in the Estrous cycle, The corpus luteum ( Latin for "yellow body" (plural corpora lutea) is a temporary Endocrine structure in mammals involved in production of It is adapted to provide an optimum environment for the implantation and growth of the embryo. An embryo (from Greek:, plural, lit "that which grows" from en- "in" + bryein "to swell be full" is a multicellular This layer is completely shed during menstruation. See also "Mensuration" a term sometimes used to describe Measurement, particularly in the context of Forestry.
- The basal layer, adjacent to the myometrium and below the functional layer, is not shed at any time during the menstrual cycle, and from it the functional layer develops. The myometrium is the middle layer of the uterine wall consisting of smooth muscle cells and supporting stromal and vascular tissue
In the absence of progesterone, the arteries supplying blood to the functional layer constrict, so that cells in that layer become ischaemic and die, leading to menstruation. In Medicine, ischemia ( Greek ισχαιμία, isch- is restriction hema or haema is Blood) is a restriction See also "Mensuration" a term sometimes used to describe Measurement, particularly in the context of Forestry.
It is possible to identify the phase of the menstrual cycle by observing histological differences at each phase:
| Phase | Days | Thickness | Epithelium |
| menstrual phase | 1-4 | thin | absent |
| proliferative phase | 4-14 | intermediate | columnar |
| secretory phase | 15-28 | thick | columnar. The follicular phase (or proliferative phase) is the phase of the Estrous cycle, (or in humans and Great apes the Menstrual cycle) during The luteal phase (or secretory phase) is the latter phase of the Menstrual cycle (in humans and a few other animals or the Estrous cycle (in other Also visible are helicine branches of uterine artery |
Pathological conditions
Adenomyosis is the growth of the endometrium into the muscle layer of the uterus (the myometrium). The helicine branches of uterine artery (or helicine arterioles, or spiral arteries) are small arteries which temporarily supply the Endometrium of the Adenomyosis is a medical condition characterized by the presence of ectopic endometrial tissue (the inner lining of the Uterus) within the myometrium (the The myometrium is the middle layer of the uterine wall consisting of smooth muscle cells and supporting stromal and vascular tissue
Endometriosis is the growth of endometrial tissue outside the uterus. Endometriosis (from endo, "inside" and metra, " Womb " is a common medical condition characterized by growth beyond or outside the uterus
Endometrial cancer is the most common cancer of the human female genital tract. Endometrial cancer refers to several types of malignancy which arise from the Endometrium, or lining of the Uterus. Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled
See also
Additional images
 Vertical section of mucous membrane of human uterus. The menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive-age Females Overt menstruation (where there is blood flow from the Oestrus is also the biological genus name of the gadfly. The estrous cycle (also oestrous cycle; derived from Latin |
.jpg/120px-Endometrial_adenocarcinoma_(1).jpg) Histopathologic representation of endometrioid adenocarcinoma demonstrated in endometrial biopsy. Hematoxylin-eosin stain. |
 Blastocyst with an inner cell mass and trophoblast. |
.JPG/120px-Uterus_(endometrium).JPG) microscopic slide of the endometrium. |
References
- ^ Blue Histology - Female Reproductive System. School of Anatomy and Human Biology - The University of Western Australia http://www.lab.anhb.uwa.edu.au/mb140/CorePages/FemaleRepro/FemaleRepro.htm Accessed 20061228 20:35
External links
- SUNY Figs 43:05-15 - "The uterus, uterine tubes and ovary with associated structures. The State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center, is an academic medical center and is the only one of its kind "
- Histology at BU 18902loa - "Female Reproductive System uterus, endometrium"
- Swiss embryology (from UL, UB, and UF) gnidation/role02
- Histology at OU 20_01
- Histology at utah.edu. Slide is proliferative phase - click forward to see secretory phase
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