Decidua is the term for the uterine lining (endometrium) during a pregnancy. It is formed under the influence of progesterone and serves to support and interact with the gestation. The decidua represents the maternal portion of the placenta. Female internal reproductive anatomy The uterus or womb is the major female reproductive organ of most mammals, including humans. ... The endometrium is the uterine membrane in mammals which is thickened in preparation for the implantation, of a fertilized egg upon its arrival into the uterus. ... Pregnancy Pregnancy is the carrying of one or more embryos or fetuses by female mammals, including humans, inside their bodies. ... Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ... The placenta is an ephemeral (temporary) organ present only in female placental mammals during gestation (pregnancy). ...

Etymology

The word comes from the Latin deciduus, meaning falling off or shedding. Latin is an ancient Indo-European language originally spoken in the region around Rome called Latium. ...

Background

After ovulation, in mammals, the endometrial lining becomes transformed into a secretory lining in preparation to accept the embryo. Without implantation the secretory lining will be absorbed (estrous cycle) or shed (menstrual cycle). With implantation the lining now termed decidua evolves further during the pregnancy. The decidua is shed during the parturition process. Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ... Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors) Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata (extinct) Perissodactyla Pholidota Plesiadapiformes... Embryos (and one tadpole) of the wrinkled frog (Rana rugosa). ... Implantation occurs when a fertilized zygote attaches itself onto the lining of the uterus. ... The estrus cycle (also Å“strus or estrous cycle) refers to the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females (humans and great apes are the only mammals who undergo a menstrual cycle instead). ... Menstrual cycle The menstrual cycle is the set of recurring physiological changes in a females body that are under the control of the reproductive hormone system and necessary for reproduction. ... Childbirth in a hospital. ...

Structure

Different layers of the deciduas have been described, a compact outer layer (stratum compactum), an intermediate layer (stratum spongiosum), and a boundary layer adjacent to the myometrium. That part of the deciduas that interacts with the trophoblast is the decidua vera (“true decidua”), the remainder of the decidua is termed the decidua parietalis. The decidua has a histologically distinct appearance displaying large polygonal decidua cells in the stroma. Vascularity is enhanced. Its leukocyte population is distinct with the presence of large endometrial granular leukocytes being predominant, while polynuclear leukocytes and B-cells are scant. The border to the trophoblast is called Nitabuch’s layer. The myometrium is the middle layer of the uterine wall consisting of smooth muscle cells and supporting stromal and vascular tissue. ... A thin section of lung tissue stained with hematoxylin and eosin. ... White Blood Cells is also the name of a White Stripes album. ...

Role

As the maternal interface to the embryo the decidua participates in the exchanges of nutrition, gas, and waste with the gestation. It also protects the pregnancy from the maternal immune system. Further, the decidua has to allow a very controlled invasion of the trophoblast. The immune system is the system of specialised cells and organs that protect an organism from outside biological influences. ...

Hormone production

The decidua secretes hormones, growth factors, and cytokines. It has receptors for estrogen, progesterone, growth hormone, and others. Among its products are hormones commonly associated with other organs such as cortisol, CRF, GnRH, prolactin, and relaxin. Decidual prolactin is not under dopaminergic control. Pregnancy protein 14 (PP-14) also called placental protein 12 and Insulin like growth factor binding protein 1(IGFBP1) appears to be a specific product of the secretory and decidual lining. Other factors released include interleukin-15, vascular endothelial growth factor (VEGF), and insulin-like growth factor binding proteins. A reasonable understanding of the role and interplay of these hormones and factors has not been evolved. Hormone is also the NATO reporting name for the Soviet/Russian Kamov Ka-25 military helicopter. ... Growth factor is a protein that acts as a signaling molecule between cells (like cytokines and hormones) that attaches to specific receptors on the surface of a target cell and promotes differentiation and maturation of these cells. ... Cytokines are small protein molecules that are the core of communication between immune system cells, and even between these cells and cells belonging to other tissue types. ... Estrogens (also oestrogens) are a group of steroid compounds that function as the primary female sex hormone. ... Progesterone is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ... Growth hormone Growth hormone is a polypeptide hormone synthesised and secreted by the anterior pituitary gland which stimulates growth and cell reproduction in humans and other vertebrate animals. ... Cortisol is a corticosteroid hormone that is involved in the response to stress; it increases blood pressure and blood sugar levels and suppresses the immune system. ... Corticotropin-releasing hormone (CRH), also called corticotropin-releasing factor (CRF) or corticoliberin, is a polypeptide hormone involved in the stress response. ... Gonadotropin Releasing Hormone (GnRH) is a peptide hormone responsible for the release of FSH and LH from the anterior pituitary. ... Prolactin is a hormone synthesised and secreted by lactotrope cells in the adenohypophysis (anterior pituitary gland). ... Categories: Possible copyright violations ... Dopamine is a chemical naturally produced in the body. ... Interleukins are a group of cytokines that are expressed by white blood cells (leukocytes, hence the -leukin) as a means of communication (inter-). The function of the immune system depends in a large part on interleukins, and rare deficiencies of a number of them have been described, all featuring autoimmune... Vascular endothelial growth factor or VEGF is an important signal protein involved in angiogenesis. ...

Other

• In case of an extrauterine pregnancy, the endometrium nevertheless becomes decidualized. A women may shed the lining in the form of a decidual cast which may be mistaken as a miscarriage, when, in fact, the ectopic still persists.
• A decidual reaction can be observed in tissue of the peritoneum and ovary during a pregnancy and represents a response of stromal tissue to progesterone.

An ectopic pregnancy is one in which the fertilized ovum is implanted in any tissue other than the uterine wall. ... Miscarriage is the common term for the natural or accidental termination of a pregnancy at a stage where the embryo or the fetus is incapable of surviving. ... In higher vertebrates, the peritoneum is the serous membrane that forms the lining of the abdominal cavity - it covers most of the intra-abdominal organs. ... Human female internal reproductive anatomy Ovaries are egg-producing reproductive organs found in female organisms. ...

External links

1. Histologic picture
2. Gray’s anatomy