Uterus Development
Introduction
This page introduces the uterus as part of the internal female reproductive tract development. Two paramesonephric ducts form from coelomic epithelium extending beside the mesonephric ducts. In the absence of Mullerian Inhibitory Factor these ducts proliferate and grow extending from the vaginal plate on the wall of the urogenital sinus to lie beside the developing ovary. The paired ducts begin to fuse from the vaginal plate end, forming the primordial body of the uterus and the unfused lateral arms form the uterine tubes.
Johannes Peter Muller (1801 - 1858) in 1830 was the first to described the duct named after him, the "Mullerian duct" also called the paramesonephric duct.
Some Recent Findings
Deutscher E, Hung-Chang Yao H. Essential roles of mesenchyme-derived beta-catenin in mouse Mullerian duct morphogenesis. Dev Biol. 2007 May 3; [Epub ahead of print] (More? [#Molecular Molecular])
Guioli S, Sekido R, Lovell-Badge R. The origin of the Mullerian duct in chick and mouse. Dev Biol. 2007 Feb 15;302(2):389-98.
"In vertebrates the female reproductive tracts derive from a pair of tubular structures called Mullerian ducts, which are composed of three elements: a canalised epithelial tube, mesenchymal cells surrounding the tube and, most externally, coelomic epithelial cells. ... We show that all Mullerian duct components derive from the coelomic epithelium in both species. Our data support a model of a Mullerian epithelial tube derived from an epithelial anlage at the mesonephros anterior end, which then segregates from the epithelium and extends caudal of its own accord, via a process involving rapid cell proliferation. This tube is surrounded by mesenchymal cells derived from local delamination of coelomic epithelium."
Paramesonephric Duct
The Mullerian duct (= paramesonephric duct, preferred terminology) paired ducts that form the epithelial lining of female reproductive organs: utererine tube, uterus, upper vaginal canal. The term "paramesonephric" duct means beside the mesonephric (Wolffian) duct, which is its anatomical location in early development. Mullerian refers to Johannes Peter Müller (1801-1858) a German scientist who specialised in comparative anatomy. These ducts initially form and then degenerate in the male.
A recent study using both chicken and mouse embryos has shown that these initially paired tubular structures derive from the coelomic epithelium. Guioli S, Sekido R, Lovell-Badge R. The origin of the Mullerian duct in chick and mouse. Dev Biol. 2006 Oct 3
"Mullerian epithelial tube derived from an epithelial anlage at the mesonephros anterior end, which then segregates from the epithelium and extends caudal of its own accord, via a process involving rapid cell proliferation. This tube is surrounded by mesenchymal cells derived from local delamination of coelomic epithelium."
Mullerian ducts have three elements:
1. a canalised epithelial tube
2. mesenchymal cells surrounding the tube
3. coelomic epithelial cells.
Uterine Development Movie
| Anterior view of development of the female uterus and vagina between Week 9 and 20.
The paramesonephric ducts (red) fuse in the midline to form the genital canal. The urogenital sinus (yellow), in contact with the paramesonephric duct, thickens to form the sinusal tubercle which extends as a solid vaginal plate, then becomes hollow as the sinovaginal bulb, finally forming the vagina. [../Movies/genital/uterus2.mov Female Internal Genitalia] (288 Kb) |
Development Overview
| File:Urogen2.jpg | File:Urogen1.jpg |
| Internal Genital Tract Differentiation |
The data below gives an overview of the timecourse of embryonic human uterine development.
stage 18 - Müllerian duct to the coelomic cavity was formed as the result of an invagination of the coelomic epithelium
stages 19-23 - duct grows independently from the invagination
week 20 - uterine horn fimbrial development begins and continues after birth
Data: Hashimoto R. Development of the human Mullerian duct in the sexually undifferentiated stage. Anat Rec A Discov Mol Cell Evol Biol. 2003 Jun;272(2):514-9.
Fetal Uterus
|
File:Paramesonephric2.jpg |
| Urogenital sinus of female human embryo of eight and a half to nine weeks old (From model by Keibel) (Image: Gray's Anatomy) | (Image modified from: Drews U, Sulak O, Schenck PA. Androgens and the development of the vagina.Biol Reprod. 2002 Oct;67(4):1353-9. PMID: 12297555) |
Fetal Uterus Growth
| Graph shows the growth during the fetal period of the uterus between week 19 and 38. | |
| File:Uterus growth.jpg | During this time the uterine circumferunce increases from about 20 mm to just under 60mm and the width increases from less than 10mm to just over 20 mm.
Uterine horn fimbrial development begins after week 20 and continues after birth. Uterine growth continues postnatally, increasing outer muscle thickness and cyclic changes in the lining with puberty. Adult external uterine orifice to the fundus is approximately 6.25 cm. |
| (Data: Soriano D, Lipitz S, Seidman DS, Maymon R, Mashiach S, Achiron R. Development of the fetal uterus between 19 and 38 weeks of gestation: in-utero ultrasonographic measurements. Hum Reprod. 1999 Jan;14(1):215-8. and other sources) | |
Newborn Uterus
(Image: Gray's Anatomy)
Uterine Tubes
The unfused portion of the paramesonephric ducts will form the uterine tubes. Note that there are several synonyms used for the paired uterine tubes or Fallopian tubes or oviducts or uterine horns.
| File:Uterine tubes sm.jpg | In the adult, the uterine tube has been described in 4 anatomical regions.
|
| File:Cat embryo ovary sm.jpg | Developing uterine tube (cat) showing relationship to ovary and degenerating mesonephros. |
| File:Odu04he.jpg | File:Odu40he.jpg |
| File:Uem021he.jpg | File:Uem022he.jpg |
| (Images: UWA Blue Histology - Female Reproductive Tract) |
Uterine Blood Supply
| File:Uterine blood supply.jpg |
Abnormalities
|
A range of uterine and vaginal anatomical anomalies based upon the abnormal development and fusion of the paramesonephric ducts and vaginal plate development.
|
| File:Unicornate.jpg | Unicornate Uterus - failure of the paramesonephric ducts to fuse. A single paramesomnephric duct has fused with the vaginal plate and now opens into the vagina, while the other forms a diverticulum. |
Uterine Duplication (uterus didelphys, double uterus, uterus didelphis) A rare uterine developmental abnormality where the paramesonephric ducts (Mullerian ducts) completely fail to fuse generating two separate uterus parts each connected to the cervix and having an ovary each.
Septate Uterus
Cervical: cervical agenesis, cervical duplication
Vaginal: Mayer-Rokitansky syndrome (MRK anomaly, Rokitansky-Küster-Hauser syndrome, RKH syndrome, RKH) congenital absence of the vagina, dyspareunia, vaginal agenesis.
Environmental Abnormalities
DES Diethylstilbestrol or diethylstilbetrol, is a drug that was prescribed to women from 1938-1971 to prevent miscarriage in high-risk pregnancies. The drug acted as a potent estrogen (mimics natural hormone) and therefore could also act as a potential endocrine disruptor. This led to a number of developing fetal reproductive tract and other abnormalities. In the female fetus, it increased risk of abnormal reproductive tract and also carcinogenic (cancer forming). In the male fetus, it increased the occurance of abnormal genitalia. The drug was banned by FDA (USA) in 1979 as a teratogen, it had previously also been used as livestock growth promoter and could have potentially entered the human food chain. (More? [endocrine2.htm Endocrine Abnormalities] | [../Defect/drugs.htm Abnormal Development - Drugs])
Links: [endocrine2.htm Endocrine Abnormalities] | [../Defect/drugs.htm Abnormal Development - Drugs] | Childrens Hospital Boston - Congenital Anomalies of the Uterus | Medical Education Image Link - Cervical agenesis | OMIM - Rokitansky-Küster-Hauser syndrome |
Vagina Development
The embryonic origin of the vagina has been a historically hotly debated issue with several different contributions and origins described.
One description shows the vagina arising by downward growth of Wolffian and Mullerian ducts. The sinovaginal bulbs are the caudal ends of the Wolffian ducts. Vaginal development is also under negative control of androgens.
An earlier understanding was that the upper part of the vagina derived from Müllerian ducts and the lower part from the sinovaginal bulbs (formed by fusion form the vaginal plate) all derived from the urogenital sinus. The terms sinovaginal bulbs and vaginal plate were first coined by Koff in 1933.
References: Koff AK. Development of the vagina in the human fetus. Contributions to Embryology No. 140, Carnegie Inst. 1933; 24:61–90.
Broad Ligament
| The broad ligament is found associated with the internal human female genital tract. It forms a mesentery consisting of a double fold of the peritoneum that connects the uterus to the peritoneal floor and walls.
Anatomically it has three parts:
Abnormalities include peritoneal endometriosis. |
File:Image1161.gif |
Molecular
Wnt genes - Wnt4, Wnt5a, and Wnt7a implicated in the formation and morphogenesis of the Müllerian duct.
Wnt7a - mediates the patterning of the oviduct and differentiation of the uterus.
beta-catenin - manufactured in the mesenchyme is a downstream effector of Wnt7a.
Bmp2 - decidualization regulator of gene expression and function (shown in mouse uterus).
Lim1, Lhx9, Emx, Pax-2, Hox-A9, Hox-A10, Hox-A11, Hox-A13, WT1, SF-1, GATA-4. TGF-beta
References
Links: [#Reviews Reviews] | [#Articles Articles] | [#OnlineTextbooks Online Textbooks] | [#SearchTextbooks Search Textbooks] | [#SearchPubMed Search PubMed] | [#Glossary Glossary]
Reviews
Farage M, Maibach H. Lifetime changes in the vulva and vagina. Arch Gynecol Obstet. 2006 Jan;273(4):195-202.
Kavlock R, Cummings A [See Related Articles] Function of sexual glands and mechanism of sex differentiation. J Toxicol Sci. 2004 Aug;29(3):167-78. Review.
Articles
Deutscher E, Hung-Chang Yao H. Essential roles of mesenchyme-derived beta-catenin in mouse Mullerian duct morphogenesis. Dev Biol. 2007 May 3; [Epub ahead of print] (More? [#Molecular Molecular])
Guioli S, Sekido R, Lovell-Badge R. The origin of the Mullerian duct in chick and mouse. Dev Biol. 2007 Feb 15;302(2):389-98. Hashimoto R. Development of the human Mullerian duct in the sexually undifferentiated stage. Anat Rec A Discov Mol Cell Evol Biol. 2003 Jun;272(2):514-9. Soriano D, Lipitz S, Seidman DS, Maymon R, Mashiach S, Achiron R. Development of the fetal uterus between 19 and 38 weeks of gestation: in-utero ultrasonographic measurements. Hum Reprod. 1999 Jan;14(1):215-8.
Search PubMed
Search May 2007 "embryonic uterine development" 3,025 reference articles of which 491 were reviews.
Search PubMed: term = embryonic uterine development | Uterine Development | Paramesonephric Duct | Mullerian Duct | Endocrine Disruptors
Glossary
Use the alphabetical list below to find definitions of terms that are new to you or use the Google search window to search UNSW Embryology site.
| [Index/B.htm B] | [Index/C.htm C] | [Index/D.htm D] | [Index/E.htm E] | [Index/F.htm F] | [Index/G.htm G] | [Index/H.htm H] | [Index/I.htm I] | [Index/J.htm J] | [Index/K.htm K] | [Index/L.htm L] | [Index/M.htm M] | [Index/N.htm N] | [Index/O.htm O] | [Index/P.htm P] | [Index/Q.htm Q] | [Index/R.htm R] | [Index/S.htm S] | [Index/T.htm T] | [Index/U.htm U] | [Index/V.htm V] | [Index/W.htm W] [Index/X.htm X] | [Index/Y.htm Y] | [Index/Z.htm Z] |
Terms
abdomen - trunk between diaphragm and pelvis.
abdominal circumference - An ultrasound measurement of Abdominal Circumference (AC) is used to determine fetal age and normal development (small/large/abnormal) parameters. Measured at the outer edge of the circumference of the body plane in which the portal vein or stomach can be visualized in a tangential section. It is one of the four typical ultrasound assessments of fetal size and age: [index/B.htm#biparietal_diameter Biparietal Diameter] (BPD), [index/H.htm#head_circumference Head Circumference] (HC), Abdominal Circumference (AC), and [index/F.htm#femur_length Femur Length] (FL). Abdominal Circumference of less than 31 cm at 36 to 40 weeks gestation is a predictor of intrauterine growth retardation (IUGR). (More? [../Movies/ultrasound.htm Ultrasound] | [../head.htm Head Notes]) | [../wwwhuman/Fetus.htm Fetal Notes] | [../Child/birth1.htm Birth Notes] | [../Defect/IUGR.htm Intrauterine Growth Retardation])
AC - Acronym for [#abdominal_circumference Abdominal Circumference].
acrosome reaction - The chemical change that enables release of acrosomal contents and allow a sperm to penetrate an egg. (More? [week1_3b.htm Spermatogenesis] | [week1_5.htm Fertilization])
adenohypophysis - (anterior pituitary, pars distalis) The anterior part of the pituitary, which develops in the early embryo from a transient region on the roof of the pharynx called Rathke's pouch. (More? [endocrine7.htm Endocrine Development - Pituitary])
adnexa - (Latin, adnexae = appendages) Term used to describe any anatomical appendage (accessory structure, extension or outgrowth from the body). In reproductive anatomy used to describe appendages of the [U.htm#uterus uterus] "body"; ovaries, uterine tubes and uterus supporting ligaments.
adrenal gland - (suprarenal gland) The endocrine organ that anatomically sits on top of the kidneys (renal). It has two different embryonic origins, neurat crest (aderenal medulla) and mesoderm (adrenal cortex). (More? [endocrine9.htm Endocrine Notes - Adrenal Gland])
adventitia - Anatomical term describing the outermost connective tissue covering of any organ, vessel, or other structure not covered by a serosa. The covering is from the surrounding connective tissue and does not form an integral part of such organ or structure.
allantois - An [E.htm#extraembryonic_membrane extraembryonic membrane], endoderm in origin extension from the early hindgut, then cloaca into the connecting stalk of placental animals, connected to the superior end of developing bladder. In reptiles and birds, acts as a reservoir for wastes and mediates gas exchange. In mammals is associated/incorporated with connecting stalk/placental cord fetal-maternal interface. (More? [placenta.htm Placenta] | [week2.htm Week 2 Notes] | [git.htm Gastrointestinal Tract Notes])
amnion - An [E.htm#extraembryonic_membrane extraembryonic membrane] ectoderm and extraembryonic mesoderm in origin and forms the innermost fetal membrane, produces amniotic fluid. This fluid-filled sac initially lies above the trilaminar embryonic disc and with embryoic disc folding this sac is drawn ventrally to enclose (cover) the entire embryo, then fetus. The presence of this membane led to the description of reptiles, bird, and mammals as amniotes. (More? [placenta.htm Placenta Notes] | [week2.htm Week 2 Notes])
amniotic fluid - The fluid that fills amniotic cavity totally encloses and cushions the embryo. Amniotic fluid enters both the gastrointestinal and respiratory tract following rupture of the buccopharyngeal membrane. The late fetus swallows amniotic fluid.
ampulla - Term used to describe an anatomical dilation of a tube or canal lumen. Anatomical description of the opening end of the uterine tube lying above the ovary and the enlarged initial segmeny of the semicircular canals of the inner ear vestibular system. (More? [ear6.htm Inner Ear] | [genitalXXuterus.htm Genital System - Female Uterus])
anastomosis - Term used to describe the connection between two tubes. Applied to describe the connection between peripheral blood vessels without an intervening capillary bed.
androgens - The male sex hormones, eg testosterone. (More? [genitalXY.htm Genital System - Male])
anterior - Anatomical term used to describe the front or ventral surface.
Anti-Mullerian Hormone - (AMH, Mullerian Inhibiting Substance, MIS) A secreted factor (transforming growth factor-beta, TGF-beta superfamily) that regulates gonadal and genital tract development. Inhibits paramesonephric (Mullerian) duct development in males. (More? [genitalY.htm Male] | OMIM - AMH)
antral follicle - (secondary follicle) Term used to describe the developmental stage of ovarian follicle development following preantral (primary) in describing the sequence (primordial, preantral, antral) of follicle development within the ovary. In humans, a number of primordial follicles will begin to develop into primary follicles, some of which will then form antral follicles (secondary), with only a single antral follicle developing into the ovulating follicle (Graafian) each menstrual cycle. (More? [week1_3a.htm Week 1 - Oogenesis])
antrum - (Latin from Greek, antron = a cave, cavity; a nearly-closed cavity or bulge). Identified anatomically in many structures (ovarian follicle, bone, cardiac, gastric). In the ovary this refers to the follicular fluid-filled space within the follicle. (More? [week1_3a.htm Week 1 - Oogenesis])
atresia - (Greek, a = without + tresis = perforation) Term used for anatomical closing or absence of a cavity or opening that should exist. Used as an antomical, pathological and clinical term: esophageal atresia, biliary atresia, duodenal atresia, jejunal atresia, choanal atresia, vaginal atresia, urethral atresia, pulmonary atresia, bronchial atresia, tricuspid atresia. (More? see [#atretic_follicle atretic follicle])
autosomal - The term decribing all the chromosomes that contribute to a cell's genetic material, except for the sex chromosomes X, Y. (More? [../DNA/DNA.htm DNA Notes])
autosomal inheritance - Some hereditary diseases are described as autosomal which means that the disease is due to a DNA error in one of the 22 pairs that are not sex chromosomes. Both boys and girls can then inherit this error. If the error is in a sex chromosome, the inheritance is said to be sex-linked. (More? [../DNA/DNA.htm DNA Notes])
birth - (parturition) Term describing the pysiological process of offspring (child) being born. (More? [../Child/birth1.htm Normal Development - Birth])
bladder exstrophy - (Greek, ekstriphein = "turn inside out") A congenital malformation with bladder open to ventral wall of abdomen (between umbilicus and pubic symphysis) and may have other anomolies associated with failure of closure of abdominal wall and bladder (epispadias, pubic bone anomolies). (More? [urogenital2.htm Urogenital Abnormalities])
Bulbourethral Gland - (= Cowper's Gland) A male genital tract gland which secretes a small amount of a thick clear mucous fluid prior to ejaculation, the alkaline content apparently buffers acidity of the urethra. The equivalent female gland are Bartholin's glands. (More? [urogen.htm Urogenital Notes])
caudal - (Latin, caudal = tail) Anatomical term referring to structures that are more towards the tail.
chryptochid testes - A male genital abnormality where the testes remain undescended in the abdominopelvic cavity. (More? [genital2.htm#GonadalDescent Reproductive System - Abnormalities - Gonadal Descent])
ciliated epithelium - (Latin, cilium = eyelid) An epithelium named on the basis of the cells having surface hair-like appearance of a cilium; singular, cilium. In many tissues, cilia are found as epithelial cell apical surface motile specializations. In the uterine tube epithelium, after ovulation used to move the unfertilized egg, then the fertilized zygote, then blastocyst during the first week of development.
cloacal membrane - Forms the external lower membrane limit (caudal end) of the early gastrointestinal tract (GIT). This membrane is formed during gastrulation by ectoderm and endoderm without a middle (intervening) layer of mesoderm. The membrane breaks down to form the initial "anal opening" of the gastrointestinal tract. (More? [B.htm#buccopharyngeal_membrane buccopharyngeal membrane] | [git.htm GIT Notes])
coelom - Term used to describe a space. There are extraembryonic and intraembryonic coeloms that form during vertebrate development. The single intraembryonic coelom will form the 3 major body cavities: pleural, pericardial and peritoneal. (More? [../coelom.htm Coelom Notes])
congenital - Already present at birth, often used to describe defects present at birth, congenital defects. (More? [../Defect/page1.htm Abnormal Development])
congenital adrenal hyperplasia - (CAH, adrenal virilism) Abnormality of the fetal adrenal cortex, alters cortisol and androgens with different effects dependent upon sex: in females masculization of the external genitalia; in males, disorder often unnoticed until postnatally. In both sexes, accelerated skeletal growth and sexual maturation is seen in late childhood. (More? [endocrine9.htm#CAH Endocrine Adrenal - congenital adrenal hyperplasia])
corticosteroid - A steroidal hormone produced by the adrenal cortex. (More? [endocrine.htm Endocrine Notes])
critical period - (critical period of development) The term used to describe a developmental time when exposure to a teratogen can lead to a developmental abnormality, which can be further divided into an early major and later minor developmental abnormality. The defined critical period will differ in timing and length for different systems. (More? [../Defect/page1.htm#Environmental Abnormal Development - Environmental])
CRL - Acronym for Crown-Rump Length. Used in embryology to accurately stage the early embryo. Used in clinical ultrasound as a measurement between the periods of 7 to 13 weeks as an accurate estimation of the gestational age. (More? [../wwwhuman/Stages/Stages.htm Embryo Stages] | [../Movies/ultrasound.htm Ultrasound Movies])
cryptorchidism - An abnormality of either unilateral or bilateral testicular descent, occurring in < 30% premature and 3-4% term males. Descent may complete postnatally in the first year, failure to descend can result in sterility. (More? [urogen.htm Urogenital Notes] | [genital2.htm Genital Abnormalities])
dihydrotestosterone - The hormonally active form of testosterone (male sex hormone) produced by enzyme (5-alpha reductase) conversion. In the male embryo, this can occur in the genital skin which then supports external genital development. In the adult, this conversion occurs in a number of different tissues. A known treatment for prostate cancer include 5-alpha reductase inhibitors. (More? [urogen.htm Urogenital Notes] | [endocrine.htm Endocrine Notes] )
ductuli efferentes - testis (male gonad) series of tubular structures which arise from the rete testis and conduct spermatazoa into the ductus epididymidis. Their columnar epithelium lining consisting of both absorptive and ciliated cells (giving rise to "cogwheel appearance) which removes much of the fluid associated with the spermatazoa leaving the testes (also by the upper epididymis) thereby increasing the spermatazoa concentration. (Spermatozoa Duct Pathway: seminiferous tubule ‚Üí straight tubule ‚Üí rete testis ‚Üí ductuli efferentes ‚Üí ductus epididymidis ‚Üí ductus deferens) (More? [week1_3b.htm Spermatogenesis] | [genitalXY.htm Genital - Male] | [genital.htm Genital Notes])
ductus epididymidis - (epididymidis) male testes tubular structure which arise from the ductuli efferentes and conduct spermatazoa into the ductus deferens (vas deferens). The long duct is lined by a tall pseudostratified columnar epithelium. (More? [genitalXY.htm Genital - Male] | [genital.htm Genital Notes])
ectoderm - (Greek, ecto = outside + derma = skin) One of the initial 3 germ cell layers, which will form the nervous system from the neural tube and neural crest and also generates the entire epithelial layer of the skin covering the embryo. (More? [week3.htm Week 3 Notes])
embryology - (Greek, en = in + bryein = to be full of) The science of studying embryo development, usually applied to all development before birth (in humans, included both the embryonic and fetal period). (More? [../embryo.htm UNSW Embryology] | [../wwwhuman/Stages/Stages.htm embryo stages])
endocrine - (Greek, endon = within) Glands which release hormones into the blood stream. There are many specialized organs and tissues that release hormones into the bloodstream. (More? [endocrine.htm Endocrine Notes])
endocrine gland - (Greek, endon = within) A gland (organ, tissue) that is specialized for secretion of a hormone into the bloodstream for general circulation. (More? [endocrine.htm Endocrine Notes])
endoderm - (Greek, endo = inside + derma = skin) One of the initial 3 germ cell layers, formed by the process of gastrulation. The endoderm forms as a cuboidal epithelium and contributes not only to the trilaminar embryo, but also lines the yolk sac. It will form the entire epithelial lining of the gastrointestinal tract (GIT), contribute to the accessory organs of GIT and also forms the epithelial lining of the respiratory tract. Note that in the GIT it contributes both epithelium and the associated epithelial glands. In humans, endoderm forms during week 3 of development. (More? [week3_3.htm Week 3 - Gastrulation] | [week3.htm Week 3 Notes])
epiblast - (Greek, epi = above, upon) the layer (of the bilaminar embryo) that generates endoderm and mesoderm by migration of cells through the primitive streak. The remaing cells form ectoderm.
epithelium - (Greek, epi = upon + thele = nipple) Cells tightly linked together to form a sheet with little extracellular matrix. Most epithelia (plural) in the body are embryonically derived from ectoderm or endoderm germ layers. Note: not "skin" which is the epithelium and includes the underlying connective tissue layers (mesoderm) and melanocytes (neural crest) forming a complex tissue.
epoophoron - (rete ovarii, broad ligament cyst) A group of epithelial tubules that can be located in the mesosalpinx possibly mesonephric in origin. Occurs when a segment of the mesonephric duct remains in the female, associated with either the ovary and broad ligament. This "male remnant" will appear as a cyst (broad ligament cyst, adnexal papillary cystadenoma of probable mesonephric origin, APMO) with an appearance that differs depending upon the state of differentiation when the original abnormality occurred. (More? [urogen.htm Urogenital Notes] | [genital.htm Genital Notes])
estrogens - Sex hormone found in both male and female. In the female, this hormone is produced by the ovaries and is responsible for development of secondary feminine sex characteristics. Together with progesterone these hormones also regulate changes that occur each menstral cycle. In the male, Leydig cells produce estrogen into the rete testis fluid at variable levels in different species. During male embryonic development exposure to high levels of estrogen can lead to genital abnormalities. (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle])
exstrophy - (Greek, ekstriphein = "turn inside out", bladder exstrophy, cloacal exstrophy) Term used to describe developmental abnormalities where the structure has been anatomically inverted. For example, bladder exstrophy, a congenital malformation with bladder open to ventral wall of abdomen (between umbilicus and pubic symphysis) and may have other anomolies associated with failure of closure of abdominal wall and bladder (epispadias, pubic bone anomolies).
(More? [index/B.htm#bladder_exstrophy bladder exstrophy] | [urogenital2.htm Urogenital Abnormalities])
exstrophy of the bladder - See [B.htm#bladder_exstrophy bladder exstrophy]
extraembryonic membrane - Term used to describe each of the amnion, yolk sac, allantois and chorion membranes. [index/A.htm#amnion Amniotic membrane], ectoderm origin innermost membrane, produces amniotic fluid (reptiles, bird, and mammals are amniotes). [index/A.htm#yolk_sac Yolk sac], endoderm origin, associated with nutrition in reptiles and birds (mammals source of primordial germ cells and blood cells). [index/A.htm#allantois Allantois], endoderm origin, in reptiles and birds acts as a reservoir for wastes and mediates gas exchange; in mammals is associated/incorporated with connecting stalk/placental cord fetal-maternal interface. [index/C.htm#chorion Chorioic membrane], mesoderm origin, outermost layer in reptiles and birds acts in gas exchange; in mammals incorporated into the placenta and its functions. (More? [placenta.htm Placenta] | [week2.htm Week 2 Notes] | [git.htm Gastrointestinal Tract Notes])
extraembryonic mesoderm - Cells from the conceptus that contribute to placenta and fetal membranes. Described as "extraembryonic" because it is tissue lying outside the embryonic trilaminar disc (ectoderm, mesoderm and endoderm) and "mesoderm", because of the connective tissue cellular organization. (More? [placenta.htm Placenta] | [week2.htm Week 2 Notes] | [git.htm Gastrointestinal Tract Notes])
fallopian tube - (see [#uterine_tube uterine tube], uterine horn, oviducts) A pair of tubular structures designed to transport the oocyte (egg) from the ovary to the [U.htm#uterus uterus] body, named after Gabriel Fallopius (1523-1562), an anatomists and physician.
fetal period - (foetal period) In humans, the development week 9 to 36 is the fetal stage (second and third trimester) and during this time organs formed in the embryonic period continue to develop and the fetus grows in size and weight. The first 8 weeks of development is considered the embryonic period and is divided into 23 Carnegie stages based upon developmental milestones. Note when searching an alternate spelling "foetal". (More? [../wwwhuman/fetus.htm Fetal Notes] | [../wwwhuman/Stages/Stages.htm Embryo Stages])
fetus - (foetus) In mammals, term describes the period of development following the embryonic period. In humans, the development week 9 to 36 is the fetal stage (second and third trimester). (see [#fetalperiod fetal period] above).
fimbriae - (Latin, fimbria = a fringe) The finger-like projections at the ovarian end of uterine tube. At ovulation they sit over the ovary to aid egg movement into the uterine tube. (More? [week1.htm Week 1 Notes])
Finasteride - A chemical used to prevent male pattern baldness and enlargement of prostate glands. An anti-androgen (blocks synthesis of dihydrotestosterone) and therefore a potential endocrine disruptor, exposed pregnant women can impact on male fetus genetial development. (More? [endocrine2.htm Endocrine Abnormalities])
first trimester - Clinical term used to describe and divide human pregnancy period (9 months) into three equal parts of approximately three calendar months. The first trimester corresponds approximately to embryonic development (week 1 to 8) of organogenesis and early fetal. The second and third trimester correspond to the fetal period of growth in size (second trimester) and weight (third trimester), as well as continued differentiation of existing organs and tissues. (More? [../wwwhuman/Stages/Stages.htm Embryo Stages] | [../wwwhuman/fetus.htm Human Fetal Period] | [week/weekbyweek.htm Development Week by Week])
follicle - (Latin, folliculus = little bag, dim. of Latin follis) The functional unit within the ovary that includes the developing oocyte (egg) and the surrounding layers of cells that support that oocyte. Some cells within the follicle are released along with the ooctye at ovulation, while other cells are involved with female sex hormone secretion into the maternal bloodstream. (More? [week1_3a.htm Week 1 - Oogenesis] | [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [genitalXX.htm Genital System - Female])
follicle stimulating hormone - (FSH, gonadotropin) Glycoprotein hormone secreted by anterior pituitary and acts on gametogenesis and other systems in both males and females. In females, FSH acts on the ovary to stimulate follicle development. Negative feedback by inhibin from the developing follicle decreases FSH secretion. In males, acts on the testis Sertoli cells to increase androgen-binding protein (ABP) that binds androgens and has a role in spermatogenesis. FSH-deficientcy in females results in infertile (block in folliculogenesis prior to antral follicle formation) and in males does not affect fertility (have small testes but are fertile). FSH protein has a molecular weight 30 kDa and a 3-4 hour half-life in circulation. Gonadotrophins have been used clinically in humans for the treatment of infertility. Other glycoproetin hormones include luteinizing hormone (LH), thyroid stimulating hormone (TSH), and chorionic gonadotropin. (More? [week1_3a.htm Week 1 - Oogenesis] | [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [endocrine7.htm Endocrine Development - Pituitary] | Kumar TR, Wang Y, Lu N, Matzuk MM. Follicle stimulating hormone is required for ovarian follicle maturation but not male fertility. Nat Genet. 1997 Feb;15(2):201-4.)
folliculogenesis - The term used to describe the process of [#follicle follicle] development within the ovary. The follicle is the structure developing within the ovary that includes the oocyte (egg) and surrounding support cells. (More? [week1_3a.htm Week 1 - Oogenesis] | [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [genitalXX.htm Genital System - Female])
gametes - (Greek, gamos = marriage) A specialized reproductive cell through which sexually reproducing parents pass chromosomes to their offspring; a sperm or an egg. (More? [week1.htm Week 1 Notes])
gameteogenesis - The production of either the haploid germ cells of spermatazoa (male) or eggs (female) (More? [week1.htm Week 1 Notes])
Gartner's duct - a female developmental abnormality caused by the persistance of the mesonephric duct (normally lost in females) when the ureteric bud fails to separate from the mesonephric duct. Can generate a broad ligament or vaginal cyst. Named after Hermann Treschow Gartner (1785-1827) a Danish surgeon and anatomist. (More? [genital2.htm Genital Abnormalities])
gene - A DNA sequence that is transcribed as a single unit and encodes a single polypeptide (protein) or a set of closely related polypeptides. There are approximately 20,000-25,000 protein encoding genes in the human genome. In each cell, DNA is found within the nucleus and also within mitochondria. (More? [../DNA/DNA.htm DNA Notes])
genitalia - (Latin, genitalia = ) The term used to describe either the external or internal male and female sexual and reproductive organs. (More? [urogen.htm Urogenital Notes])
genital tubercle - A prominence or rounded protuberance extending ventrally at the inferior end of the body of the embryo. It has initially a sexually indifferent external genitalia structure and contributes to either male (glans penis) and female (clitoris) external genitalia. (More? [urogen.htm Urogenital Notes])
genome - The collection of all the DNA in an organism. (More? [../DNA/DNA.htm DNA Notes])
germ layers - The first three cellular layers (ectoderm, mesoderm, and endoderm) that will form all tissues of the embryo. In humans, these layers begin to form during week 3 of development. Term should not be confused with germ cells, which are the oocyte and spermatazoa forming cells. Named originally by Robert Remak (1815 - 1865) a German scientist and embryologist. (More? [week2.htm Week 2 Notes] [week3.htm Week 3 Notes] | Robert Remak)
germinal epithelium - cellular component covering surface of ovary, it is continuous with mesothelium covering mesovarium. Note that it is a historical misnomer, as it is not the actual site of germ cell formation.
GHRH - Arconym for Growth Hormone Releasing Hormone, secreted by the Hypothalamus it is a protein that activates Growth Hormone synthesis and release from the pituitary. (More? [endocrine16.htm Endocrine Notes - Hypothalamus])
gonad - (Greek, gonos = seed) A gamete-producing (germ cell) organ. A non-sexual term which is used to describe both the female ovary and male testis. (More? [week1.htm Week 1 Notes])
gonadotrophin releasing hormone - (Greek, gonos = seed) (GnRH) Hormone released from hypothalamus that stimulates pituitary gonadotropin synthesis and secretion ([L.htm#luteinizing_hormone luteinizing hormone, LH] and [F.htm#follicle_stimulating_hormone follicle stimulating hormone, FSH]). The cyclic release of GnRH has been shown to differentially affect gonadotropin release (rapid frequency, more than 1 pulse / hour LH; slower frequencies FSH secretion). (More? [week1.htm Week 1 Notes] | Marshall JC, Eagleson CA, McCartney CR. Hypothalamic dysfunction. Mol Cell Endocrinol. 2001 Oct 25;183(1-2):29-32. Review.)
granulosa cell - A specific cell type that proliferates in association with the oocyte within the developing follicles of the ovary. These cells form the follicle stratum granulosa and are also given specific names based upon their position within the follicle. In the antral follicle, [index/M.htm#membrana_granulosa membrana granulosa] sits on the [index/F.htm#follicular_basal_lamina follicular basal lamina] and lines the antrum as a stratified epithelium. The [index/C.htm#cumulus_oophorus cumulus oophorus] isindex/ a column of granulosa cells that attaches the oocyte to the follicle wall. The [C.htm#corona_radiata corona radiata] are the granulosa cells that directly surround the oocyte, and are released along with it at ovulation. Following ovulation the corona radiata provide physical protection to the oocyte and granulosa cells within the ovulating follicle contribute to corpus luteum. (More? [week1_3a.htm Week 1 - Oogenesis] | [week1_3d.htm Corpus luteum])
growth hormone - (GH) A peptide hormone, made in the anterior pituitary, that stimulates tissue and skeletal growth. (More? [endocrine7.htm Endocrine Notes - Pituitary])
growth hormone releasing hormone - (GHRH) secreted by the hypothalamus it is a protein that activates Growth Hormone synthesis and release from the pituitary. (More? [endocrine16.htm Endocrine Notes - Hypothalamus])
hCG - An acronym for the hormone [#human_chorionic_gonadotrophin human Chorionic Gonadotrophin].
hernia - A general discription of protrusion of an organ through a weak spot in the surrounding tissue. In normal development, herniated midgut, describes the gastrointestinal tract growth outside the abdominal wall prior to body wall growth. In abnormal development, abnormal protrusion of organs in the diaphragm, abdominal or groin areas (hiatal hernias or inguinal hernias).
herniated - The discription of the process of protrusion of an organ through a weak spot in the surrounding tissue. In normal development, herniated midgut, describes the gastrointestinal tract growth outside the abdominal wall prior to body wall growth. In abnormal development, abnormal protrusion of organs in the diaphragm, abdominal or groin areas (hiatal hernias or inguinal hernias). Occurs normally in the development of the gastrointestinal tract when the midgut is initially herniated at the umbilicus during embryonic development.
hilum - Term used to describe an anatomical depression in an organ where vessels and nerves enter or leave.
hindgut - The last of the three part/division ([F.htm#foregut foregut] - [M.htm#midgut midgut] - hindgut) of the early forming gastrointestinal tract. The hindgut forms all the tract from the distral transverse colon to the cloacal membrane and extends into the connecting stalk (placental cord) as the allantois. In addition, a ventral of the hindgut will also form the urinary tract (bladder, urethra) epithelium. (More? [git.htm Gastrointestinal Tract Notes] | [urogenital.htm Urogenital Notes])
hormone - A substance, made and released by cells in a specific organ or structure, that moves throughout the organism and exerts specific effects on specific cells in other organs or structures. (More? [endocrine.htm Endocrine Notes])
human chorionic gonadotrophin - (hCG) Placental hormone initially secreted by cells (syncitiotrophoblasts) from the implanting conceptus during week two, supporting the ovarian corpus luteum, which in turn supports the endometrial lining and therefore maintains pregnancy. Hormone can be detected in maternal blood and urine and is teh basis of many pregnancy tests. Hormone also stimulates the onset of fetal gonadal steroidogenesis, high levels are teratogenic to fetal gonadal tissues. (More? [placenta.htm Placenta Notes] | [week2.htm Week 2 Notes]
hyperplasia - An abnormal increase in organ due to cell proliferation.
hypospadia - A male external genital abnormality, which is the most common penis abnormality (1 in 300) resulting from a failure of male urogenital folds to fuse in various regions and are therefore classified by the location of the opening (meatus). (More? [genital2.htm#Hypospadia Genital Abnormalities - Hypospadia] | [genital.htm Genital Notes])
ICSH - acronym for [#interstitial_cell_stimulating_hormone Interstitial Cell Stimulating Hormone] an anterior pituitary hormone. (More? [#interstitial_cell_stimulating_hormone Interstitial Cell Stimulating Hormone])
inferior - Anatomical term meaning below, beneath or lying below, a relative anatomical term.
inguinal canal - The anatomical pathway for male testes descent from the abdominal cavity (fetal) into the scrotum. (More? [genitalXY.htm Genital System - Male] | [genital2.htm#GonadalDescent Genital Notes - Gonadal Descent])
interstitial cell - (Leydig cell) Alternative name for [#Leydig Leydig cell] found within the male gonad (testis). A cell that is involved in androgen (testosterone) production. (More? [genitalXY.htm Genital System - Male] | [endocrine15.htm Endocrine Development - Gonads])
interstitial cell stimulating hormone - (ICSH, gonadotropin, lutropin, Interstitial Cell Stimulating Hormone, ICSH) Glycoprotein hormone releasd from anterior pituitary hormone that acts on the gonad and has a role in male and female reproduction. In male, stimulates testis interstital cell (Leydig cell) production of testosterone. In female, increase in concentration during the menstrual cycle triggers ovulation (release of the oocyte). (More? [endocrine15.htm Endocrine Development - Gonads] | [genitalXY.htm Genital System - Male])
intraembryonic coelom - The "horseshoe-shaped" space (cavity) that forms initially in the third week of development in the lateral plate mesoderm that will eventually form the 3 main body cavities: pericardial, pleural, peritoneal. The intraembryonic coelom communicates transiently with the extraembryonic coelom.
(More? [../coelom.htm Coelom Notes] | [week3.htm Week 3 Notes])
intrauterine - Term means lying within the [U.htm#uterus uterus].
karyotype - (Greek, karyon = kernel or nucleus + typos = stamp) Term used to describe the chromosomal (genetic) makeup (complement) of a cell. (More? [week1.htm Week 1 Notes] | [../Defect/genetic.htm Genetic Abnormalities])
kidney - In humans the metanephros forms the final adult kidney. An excretory organ which also has endocrine functions. (More? [urogen.htm Urogenital Notes])
Leydig cells - (interstitial cells) Testis (male gonad) cell which secrete testosterone, beginning in the fetus. These cells are named after Franz von Leydig (1821 - 1908) a German scientist who histologically described these cells. (More? [genital.htm Genital Notes] | [urogen.htm Urogenital Notes])
ligamentum teres - (ligamentum teres uteri, Hunter's ligament) The round ligament of [#uterus uterus] which maintains the ventral uterine position.
lobule - Term used to describe a small lobe. Can be used to describe part of a gland, ear, organ structure.
luteinizing hormone - (LH, gonadotropin, lutropin, Interstitial Cell Stimulating Hormone, ICSH) Glycoprotein hormone releasd from anterior pituitary hormone that acts on the gonad and has a role in male and female reproduction. In female, increase in concentration during the menstrual cycle triggers ovulation (release of the oocyte). In male, stimulates testis interstital cell (Leydig cell) production of testosterone. Gonadotrophins have been used clinically in humans for the treatment of female infertility. (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [genital.htm Genital Notes])
lutenizing hormone - alternative spelling, (LH, gonadotropin) - (LH, gonadotropin, lutropin, Interstitial Cell Stimulating Hormone, ICSH) Glycoprotein hormone releasd from anterior pituitary hormone that acts on the gonad and has a role in male and female reproduction. In female, increase in concentration during the menstrual cycle triggers ovulation (release of the oocyte). In male, stimulates testis interstital cell (Leydig cell) production of testosterone. (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [genital.htm Genital Notes])
luteinizing hormone/chorionic gonadotropin receptor - (LHCGR) a G protein-coupled receptor expressed in male testis (Leydig cells) and female ovary (granulosa-lutein and theca cells) (More? [genital.htm Genital Notes])
male factor - Any cause of infertility due to deficiencies in sperm quantity, function, or motility (ability to move) that make it difficult for a sperm to fertilize an egg under normal conditions. (More? [week1.htm Week 1 Notes])
medial - (Latin, medialis = middle) Anatomically towards the midline of the body or structure. The opposite term is lateral.
mediastinum testis - (Latin, medialis = middle) A single conical mass of connective tissue within the testis (male gonad) which extends from the tunica albuginea (cortical thick capsule surrounding the testis) into the seminiferous tubule region (medullary). Embedded within this connective tissue are the rete testis component of the duct conduction system for spermatazoa (Spermatozoa Duct Pathway: seminiferous tubule ‚Üí straight tubule ‚Üí rete testis ‚Üí ductuli efferentes ‚Üí ductus epididymidis ‚Üí ductus deferens) (More? [week1_3b.htm Spermatogenesis])
meiotic sex chromosome inactivation - (MSCI) The process of transcriptional silencing of the X and Y chromosomes that occurs only during male meiotic spermatogenesis. This is a specialised form of [#MSUC meiotic silencing of unsynapsed chromatin]. This specific silencing has also be called the second form of X chromosome inactivation, the first form occurs in all female embryo cells. (More? Meiotic sex chromosome inactivation. Turner JM. Development. 2007 May;134(10):1823-31.)
mesenchyme - Term used to describe the cellular organisation of undifferentiated embryonic connective tissue . Mesenchymal tissue is mainly derived from mesoderm and neural crest, which will form most of the adult connective tissues. This connective tissue organization contrasts with the other main form of cellular organization, epithelial tissue. (More? [skmus.htm Musculoskeletal Notes])
mesonephros - The second temporary stage of kidney development (pro-, meso-, meta-). The intermediate mesonephros develops and disappears with the exception of its duct, the mesonephric duct, which will form the male reproductive duct system. In males, the mesonephric tubules go on to form the ducts of the testis. In females, these degenerate. A few mesonephric tubules remain as efferent ductules in the male and vestigial remnants in the female. (More? [urogen.htm Urogenital Notes])
mesonephric duct - (= Wollfian duct) An early developing urogenital paired duct system that initially runs the length of the embryo, that will differentiate and form the male reproductive duct system (ductus deferens). In females, this duct degenerates occasionally some remnants may remain associated in broad ligament. (More? [genital.htm Genital Notes])
mesorchium - A peritoneal fold attaching testes to the mesonephros during development. (More? [genital.htm Genital Notes])
mesovarium - The mesentry of the ovary formed from a fold of the broad ligament that attaches the ovary. (More? [week1.htm Week 1 Notes])
metanephros - The adult kidney, third stage of mammalian kidney (pro-, meso-, meta-) development within the intermediate mesoderm. (More? [urogen.htm Urogenital Notes])
metanephric cap - In kidney development, the intermediate mesoderm ([#metanephric_mesenchyme metanephric mesenchyme]) which surrounds the ureteric bud and will develop into nephrons. (More? [urogen.htm Urogenital Notes])
metanephric mesenchyme - Metanephric mesenchyme caudal part of intermediate mesoderm that will develop into nephrons within the kidney. The intermediate mesoderm forms as an unsegmented strip running rostro-caudally between the somite and lateral plate mesoderm. The very caudal (tail) end of this mesoderm strip where the uteric bud forms is the metanephric mesenchyme, which induces the formation of, and surrounds the end of, the ureteric bud. (More? [urogen.htm Urogenital Notes])
midgut - The middle of the three part/division ([index/F.htm#foregut foregut] - midgut - [index/H.htm#hindgut hindgut]) of the early forming gastrointestinal tract. The midgut is initially connected on the ventral embryo surface to the external yolk sac by a yolk stalk, a narrow tubular connection. The midgut forms all the tract from beneath the stomach (duodenum, small intestine and large intestine) to the distral transverse colon. The midgut develops as an external loop "herniated" ventrally, until early fetal growth of the body wall recaptures this external loop, which also undergoes a rotation about the superior mesenteric artery to establish the adult anatomical position. (More? [git13.htm Gastrointestinal Tract - Intestine] | [git.htm Gastrointestinal Tract Notes])
Müllerian Duct - ([P.htm#paramesonephric paramesonephric duct]) An embryonic paired duct system that will form the epithelial lining of female reproductive organs: utererine tube, [U.htm#uterus uterus], upper vaginal canal. This duct system degenerate in male gonadal development. Named after Johannes Peter Müller (1801-1858) a German scientist. (More? [genitalXXuterus.htm Uterus Development] | [genitalXX.htm Genital System - Female] | [genitalX.htm X chromosome] | [../wwwhuman/MCycle/Mcycle.htm Human Menstrual Cycle] | [genital.htm Genital Notes])
Johannes Peter Müllerian - Johannes Peter Muller (1801 - 1858) in 1830 was the first to describe the duct named after him, the "Mullerian duct" also called the paramesonephric duct. (More? [genitalXXuterus.htm Uterus Development] | [genitalXX.htm Genital System - Female] | [genitalX.htm X chromosome] | [../wwwhuman/MCycle/Mcycle.htm Human Menstrual Cycle] | [genital.htm Genital Notes])
Mullerian Inhibiting Substance - (MIS, Anti-Mullerian Hormone, AMH, Mullerian inhibiting hormone, MIH). A sertoli cell secreted glycoprotein (transforming growth factor-beta, TGF-beta superfamily) that regulates gonadal and genital tract development. The main role is to inhibit paramesonephric (Mullerian) duct development in males. Postnatally, after puberty it is also expressed in females by ovarian granulosa cells and has a role in follicle development. (More? [genitalY.htm Male] | OMIM - AMH)
nephron - (Greek, nephros = kidney) The functional unit of the kidney. [urogenital.htm Urogenital Notes]
nephros - (Greek, nephros = kidney) Term used to describe features associated with the kidney. (pronephros, mesonephros, metanephros, nephric, nephron, nephroblastoma) [urogenital.htm Urogenital Notes]
oviduct - (uterine horn, fallopian tube, oviduct, salpinx) see [#uterine_tube uterine tube]. A pair of tubular structures designed to transport the oocyte (egg) from the ovary to the [U.htm#uterus uterus] body. (More? [week1_3a.htm Week 1 - Oogenesis] | [week1.htm Week 1 Notes] | Blue Histology - Female Reproductive System)
paramesonephric duct - (also called [index/M.htm#Mullerian_duct Mullerian duct]) (Greek, para = "beside") The paired ducts that lie beside the [index/M.htm#mesonephric_duct mesonephric ducts], that will differentiate in the female embryo to form the female internal genital tract (uterine tubes, [U.htm#uterus uterus], upper vaginal canal). (More? [urogen.htm Urogenital Notes])
parietal pleura - Serous membrane which forms the outer lining of pleural cavity. Mesoderm of the thoracic cavity body wall and derived from epithelia of pericardioperitoneal canals from intraembryonic coelom. The inner pleural layer, visceral pleura, is splanchnic mesoderm in origin. (More? [respire.htm Respiratory Notes])
peritoneal cavity - The anatomical body cavity in which the lower body organs lie: intestines, liver, bladder, [index/U.htm#uterus uterus], ovary. The peritoneal cavity forms initially from two separate regions of the early intraembryonic coelom (formed in the lateral plate mesoderm), which with embryo folding, fuse to form a single cavity. Note the single intraembryonic coelom forms all three major body cavities: pericardial, pleural, peritoneal. (More? [../coelom.htm Coelomic Cavity Notes] | [git.htm Gastrointestinal Tract Notes])
peritubular cells - (peritubular myoid cells) stromal cells (mesenchymal) located in the male gonad (testis) seminiferous tubule lying outside the basal membrane in the lamina propria surrounding seminiferous tubulus that regulate Sertoli cell function and contractility of seminiferous tubules. Also used to describe cells found in the kidney glomerulus. (More? [week1_3b.htm Week 1 - Spermatogenesis])
PGC - acronym for Primordial Germ Cell, the embryonic cell that will form eventually either egg or sperm cell. (More? [genital.htm Genital Notes] | [../Movies/genital/germcell.htm primordial germ cell movies])
Pouch of Douglas - (rectouterine pouch or rectovaginal) A female anatomical region describing the portion of the peritoneal cavity lying between the back wall of the [U.htm#uterus uterus] and rectum.
preantral follicle - ([#primary_follicle primary follicle]) Term used to describe the developmental stage of ovarian follicle development following primordial in describing the sequence (primordial, preantral, antral) of follicle development within the ovary. In humans, a number of primordial follicles will begin to develop into preantral follicles (primary), some of which will then form antral follicles (secondary), with only a single antral follicle developing into the ovulating follicle (Graafian) each menstrual cycle. (More? [week1_3a.htm Week 1 - Oogenesis])
primary follicle - ([#preantral_follicle preantral follicle]) Term used to describe the developmental stage of ovarian follicle development following primordial in describing the sequence (primordial, primary, secondary) of follicle development within the ovary. In humans, a number of primordial follicles will begin to develop into primary follicles, some of which will then form secondary (antral follicles), with only a single antral follicle developing into the ovulating follicle (Graafian) each menstrual cycle. (More? [week1_3a.htm Week 1 - Oogenesis])
primordial follicle - Present in the ovary from birth, located in the stroma of the ovary cortex beneath the tunica albuginea. The primordial follicle is the oocyte and the surrounding follicular cells. (More? [week1.htm Week 1 Notes])
primordial germ cell - Term used to describe either the sperm progenitor in the embryonic testes or oocyte progenitor present in the primordial follicle ovary from birth, located in the stroma of the ovary cortex beneath the tunica albuginea. The primordial follicle is the oocyte and the surrounding follicular cells. ([week1.htm More? Week 1 Notes])
processus vaginalis - A transient communicating channel in testes development between tunica vaginalis and peritoneal cavity. (More? [urogen.htm Urogenital Notes])
progesterone - A steroidal hormone of the progestogens class, which has many roles in the female. Functions include regulation of the menstrual cycle, uterine changes, maintaining pregnancy and effects on systems throughout the body. Biological sources include: adrenal glands, gonads (corpus luteum), brain, and placenta. Male progesterone has a suggested role in neural development. Progesterone is also used clinically as a part of hormone replacement therapy (HRT) in women. The human progesterone receptor has two isoforms (PRA and PRB). (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle])
progestins - these compounds are synthetically produced progestogens used clinically and experimentally. (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle])
prolactin - (PRL) anterior pituitary hormone which stimulates breast development and milk production in pregnancy. Also has a role in regulating follicle stimulating hormone (FSH) effect on the ovary. Protein hormone is similar in structure to both growth hormone (anterior pituitary) and chorionic somatomammotropin (placenta). Anterior pituitary release of prolactin is in turn regulated by the hypothalamus [#prolactin-releasing_hormone prolactin-releasing hormone] (PRLH, prolactin-releasing peptide). Recently been shown to to mimic in pregnancy effects of increased maternal myelination processes (oligodendrocyte precursor proliferation). (More? [endocrine7.htm Endocrine Development - Pituitary] | [../Child/milk1.htm Normal Development - Milk] | OMIM - PRL)
prolactin-releasing hormone - (PRLH, prolactin-releasing peptide, PRRP) an 87 amino acid peptide hypothalamus hormone which regulates anterior pituitary release of prolactin. (More? [endocrine16.htm Endocrine Development - Hypothalamus] | OMIM - PRLH)
puberty - (Latin, pubertas = adulthood) process involving maturation of the reproductive system. A complex process, initiated by an unknown mechanism, but involving the brain driving the hormonal axis. (More? [endocrine15.htm Endocrine Notes - Gonad] | [../Child/puberty.htm Puberty Notes])
raphé - Anatomical line of fusion of the urogenital folds lying along the urethra and scrotum in male external genitalia. (More? [urogen.htm Urogenital Notes])
rectouterine pouch - (Pouch of Douglas or rectovaginal) Anatomical description of the female peritoneal cavity lying between the back wall of the [U.htm#uterus uterus] and rectum.
renal - (Latin, renes = kidney) Term used in relation to the kidney and associated structures (renal pelvis, renal artery) (More?[urogen.htm Urogenital Notes])
rete ovarii - A group of epithelial tubules located at the hilum of the ovary possibly mesonephric origin. (More? [urogen.htm Urogenital Notes])
rete testis - The duct (epithelial tubules) conduction system for spermatazoa embedded within the mediastinum (connective tissue) located in the center of the testis (male gonad) derived from the mesonephric duct, and allow spermatazoa to travel from the seminiferous tubules to the vasa efferentia. (Spermatozoa Duct Pathway: seminiferous tubule ‚Üí straight tubule ‚Üí rete testis ‚Üí ductuli efferentes ‚Üí ductus epididymidis ‚Üí ductus deferens) (More? [week1_3b.htm Spermatogenesis] | [urogen.htm Urogenital Notes])
second trimester - Clinical term used to describe and divide human pregnancy period (9 months) into three equal parts of approximately three calendar months. The first trimester corresponds approximately to embryonic development (week 1 to 8) of organogenesis and early fetal. The second and third trimester correspond to the fetal period of growth in size (second trimester) and weight (third trimester), as well as continued differentiation of existing organs and tissues. (More? [../wwwhuman/Stages/Stages.htm Embryo Stages] | [../wwwhuman/fetus.htm Human Fetal Period] | [../week/weekbyweek.htm Development Week by Week])
Sertoli cells - The supporting cells in the testes (male gonad) that induce primordial germ cells to commit to sperm development. Support is nutritional and mechanical, as well as forming a blood-testis barrier. In development these cells secrete anti-Müllerian hormone, which causes the Müllerian (paramesonephric) duct to regress, and help to induce other somatic cells to differentiate into Leydig cells. The cells are named after Enrico Sertoli (1842 - 1910), and italian physiologist and histologist. (More? [urogen.htm Urogenital Notes] | Enrico Sertoli | UWA Blue Histology - Male Reproductive System)
spermatogonia - The cells located in the seminiferous tubule adjacent to the basal membrane that either divide and separate to renew the stem cell population, or they divide and stay together as a pair (Apr spermatogonia) connected by an intercellular cytoplasmic bridge to differentiate and eventually form spermatazoa. (More? [week1_3b.htm Week 1 - Spermatogenesis])
spermatogonial stem cells - The spermatagonia cells located beside the seminiferous tubule basal membrane that either divide and separate to renew the stem cell population, or they divide and stay together as a pair (Apr spermatogonia) connected by an intercellular cytoplasmic bridge to differentiate and eventually form spermatazoa. (More? [week1_3b.htm Week 1 - Spermatogenesis])
splanchnic mesoderm - Gastrointestinal tract (endoderm) associated mesoderm formed from the splitting of the lateral plate mesoderm. This mesoderm is the embryonic origin of the gastrointestinal tract connective tissue, smooth muscle, blood vessels and contribute to organ development (pancreas, spleen, liver). The same lateral plate mesoderm lying above the buccopharygeal membrane will form the heart. The cavity in the lateral plate mesoderm (intraembryonic coelom) will form the three major body cavities including the peritoneal cavity of the gut. The other half of the lateral plate mesoderm (somatic mesoderm) is associated with ectoderm and the body wall. (More? [week3.htm Week 3] | [git.htm Gastrointestinal Tract Notes] | [heart.htm Heart Notes] )
sry - (Sry, human; Testis-Determining Factor, TDF; Testis-Determining Factor on Y, TDY ) Gene name sex-determining region of Y, the gene locus on the Y chromosome encoding the male "testis determining factor", a protein transcription factor and a member of the high mobility group (HMG)-box family of DNA binding proteins. See also the transcription factor SRY-related protein, SOX9 (SRY-related high-mobility group (HMG) box 9) (More? [../MolDev/MolDev.htm Molecular Notes] | [week1.htm Week 1 Notes] | OMIM)
straight tubule - (tubulus rectus) A structure within the testis (male gonad) a tubular system connecting seminiferous tubule to the rete testis within the mediastinum. (Spermatozoa Duct Pathway: seminiferous tubule ‚Üí straight tubule ‚Üí rete testis ‚Üí ductuli efferentes ‚Üí ductus epididymidis ‚Üí ductus deferens) (More? [week1_3b.htm Spermatogenesis]
stromal cells - (Greek, stroma = "a cover, table-cloth, bedding") Descriptive term in the ovary, for cells surrounding the developing follicle that form a connective tissue sheath (theca folliculi). This layer then differentiates into 2 layers (theca interna, theca externa). This region is vascularized and involved in hormone secretion. (More? [week1.htm Week 1 Notes])
testes - (Latin testis = "witness") The two male gonads (singular testis) where male germ cells (spermatozoa) are generated and also the source of testosterone (male hormone). Embryonically formed from primordial germ cells entering region of the paired mesonephric ducts (Wolffian ducts) which are preserved in male gonad development and lost in females. (More? [genitalXY.htm Genital System - Male])
testis - (Latin testis = "witness", plural testes) The male gonad where male germ cells (spermatozoa) are generated and also the source of testosterone (male hormone). Embryonically formed from primordial germ cells entering region of the paired mesonephric ducts (Wolffian ducts) which are preserved in male gonad development and lost in females. (More? [genitalXY.htm Genital System - Male])
testis-determining factor - (TDF, Sry, Testis-Determining Factor on Y, TDY ) Protein name for the protein transcription factor product of the Sry gene on the Y chromosome responsible for maleness. This protein is a member of the high mobility group (HMG)-box family of DNA binding proteins. See also the transcription factor SRY-related protein, SOX9 (SRY-related high-mobility group (HMG) box 9) (More? [../MolDev/MolDev.htm Molecular Notes] | [week1.htm Week 1 Notes] | OMIM)
theca externa - (Greek, thek = box) The ovarian follicle stromal cells forming the outer layer of the theca folliculi surrounding the developing follicle within the ovary. Consisting of connective tissue cells, smooth muscle and collagen fibers. (More? [week1_3a.htm Week 1 Notes - Oogenesis] | [urogen.htm Urogenital Notes])
theca interna - (Greek, thek = box) The ovarian follicle endocrine cells forming the inner layer of the theca folliculi surrounding the developing follicle within the ovary. This vascularized layer of cells respond to leutenizing hormone (LH) synthesizing and secreting androgens (androstendione) transported to glomerulosa cells which process initially into testosterone and then by aromatase into estrogen (estradiol). Theca cells do not begin hormonal functions until puberty. (More? [week1_3a.htm Week 1 Notes - Oogenesis] | [urogen.htm Urogenital Notes])
third trimester - Clinical term used to describe and divide human pregnancy period (9 months) into three equal parts of approximately three calendar months. The third trimester corresponds to the fetal period of growth in weight, as well as continued differentiation of existing organs and tissues. The respiratory system matures late in teh third trimester. The first trimester corresponds approximately to embryonic development (week 1 to 8) of organogenesis and early fetal period, the second trimester is the fetal period of growth in size. (More? [../wwwhuman/Stages/Stages.htm Embryo Stages] | [../wwwhuman/fetus.htm Human Fetal Period] | [../week/weekbyweek.htm Development Week by Week]) trilaminar embryo Term meaning three (3) layered embryo, used to describe the early embryo development following gastrulation when it now has a structure consisting of the 3 germ cell layers (ectoderm, mesoderm, endoderm). In humans, this developmental stage occurs during week 3. (More? [week3_4.htm Week 3 - Trilaminar Embryo] | [week%203.htm Week 3] | [../wwwhuman/Stages/Stages.htm Embryo Stages] | [../week/weekbyweek.htm#week3 Development Week by Week])
trimegestone - A synthetic progesterone potentially used in postmenopausal women (with an intact [index/U.htm#uterus uterus]) in combination with estrogen as hormone-replacement therapy (HRT). (Other Progestins: levonorgestrel, 3-keto-desogestrel, dienogest, drospirenone, Nestorone and nomegestrol acetate ) Note that Trimegestone and Nestorone are currently the most potent fourth-generation progestins with no androgenic or estrogenic actions. (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle])
trimester - Clinical term used to describe and divide human pregnancy period (9 months) into three equal parts of approximately three calendar months. The first trimester corresponds approximately to embryonic development (week 1 to 8) of organogenesis and early fetal. The second and third trimester correspond to the fetal period of growth in size (second trimester) and weight (third trimester), as well as continued differentiation of existing organs and tissues. (More? [../wwwhuman/Stages/Stages.htm Embryo Stages] | [../wwwhuman/fetus.htm Human Fetal Period] | [week/weekbyweek.htm Development Week by Week])
tubulogenesis - Term used to describe the development of branched tubes from an initially unbranched epithelial bud. A fundamental process in the development of many organ systems (pancreas, mammary gland, lung, and kidney). (More? [week1.htm Week 1 Notes])
tubulus rectus - (straight tubule) Anatomical structure within the testis (male gonad) a tubular system connecting seminiferous tubule to the rete testis within the mediastinum. (Spermatozoa Duct Pathway: seminiferous tubule ‚Üí straight tubule ‚Üí rete testis ‚Üí ductuli efferentes ‚Üí ductus epididymidis ‚Üí ductus deferens) (More? [week1_3b.htm Spermatogenesis])
tunica albuginea - A dense connective tissue layer lying between germinal epithelium and cortical region of female ovary, or the equivilaent capsule of the male testis. (More? [week1.htm Week 1 Notes])
ultrasound - A noninvasive technique for visualizing and prenatal diagnosis of several features of development including: follicles in the ovaries, the gestational sac, fetus in the [U.htm#uterus uterus], fetal parameters, and the placenta. Uses high-frequency sound waves that are reflected off internal structures. These reflections can be analysed and displayed by computer. (More?[../Movies/ultrasound.htm#UltrasoundMeasurements Ultrasound Measurements] | [../Movies/ultrasound.htm Ultrasound Movies] | [../Movies/ultrasoundabnormal.htm Abnormal Ultrasound Movies])
ureter - The ureters are hollow tubes that link and carry urine from each kidney to the bladder. The tubes have a muscular wall lined with transitional epithelium. (More? [urogen.htm Urogenital Notes])
urethra - The single muscular tube that links and carries urine from the bladder to the exterior. In humans, the urethral length differs between the sexes (male longer, female shorter). (More? [urogen.htm Urogenital Notes])
urinary - Term used to describe all components of the kidney system including the bladder, ureters and urethra. (More? [urogen.htm Urogenital Notes])
urine - Term used to describe the liquid waste produced by the kidney, stored in the bladder and excreted from the body through the urethra. (More? [urogen.htm Urogenital Notes])
urorectal septum - (URS) The structure which develops to separate the cloaca (common urogenital sinus) into an anterior urinary part and a posterior rectal part. (More? [urogen.htm Urogenital Notes])
URSMS - An acronym for urorectal septum malformation sequence, clinically describing abnormalities of the urorectal septum (URS) and urogenital organs. (More? [urogen2.htm Urogenital Abnormalities] | [urogen.htm Urogenital Notes])
urinary bladder - muscular sac for the storage of urine. (More? [urogen.htm Urogenital Notes])
uterine horn - (fallopian tube, oviduct, salpinx) see [#uterine_tube uterine tube].
uterine peristalsis - rhythmic muscular contraction of the [#uterus uterus] which occurs during the menstrual cycle, maximally just before ovulation, in the non-pregnant [#uterus uterus]. (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [genitalXXuterus.htm Genital System - Female Uterus] | [urogen.htm Urogenital Notes])
uterine tube - (uterine horn, oviduct, fallopian tube, salpinx) A pair of tubular structures that transport the oocyte (egg) from the ovary to the [#uterus uterus] body. They are located laterally on the upper uterus and consist medial to lateral of three main parts: isthmus (medial constricted third), ampulla (intermediate dilated portion) and infundibulum (containing the abdominal opening/ostium, surrounded by finger-like fimbriæ). The tube has structurally several layers: a lining mucosa (mix of ciliated and secretory epithelium), a middle muscularis layer (inner circular muscle layer and an outer longitudinal layer) and outer serous layer (peritoneal). (More? [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [genitalXXuterus.htm Genital System - Female Uterus] | [urogen.htm Urogenital Notes])
uterus - The female internal genital (reproductive) tract forming a hollow muscular walled organ, embryonically derived from the [P.htm#paramesonephric paramesonephric ducts]. The human uterus has two uterine tubes (fallopian tubes, oviducts) where the first week of development occurs and a single hollow body where implantation of the blastocyst normally occurs. Following puberty, the non-pregnant uterus (epithelium and underlying stroma) undergoes cyclic changes under the influence of hormones, the menstrual cycle. This cycle of uterine changes ceases during pregnancy. In other species females of non-primate vertebrates (eg rats, mice, horses, pig) have a reproductive cycle called the estrous cycle (oestrous, British spelling). In pregnancy, the uterus contributes the maternal component of the placenta. (More? [genitalXXuterus.htm Genital System - Female Uterus] | [../wwwhuman/MCycle/MCycle.htm Human Menstrual Cycle] | [genital.htm Genital Notes])
villi - Plural of villus, which is a thin projection from a surface.
vitelline duct - (yolk stalk) Is a narrow endodermal channel between the yolk sac and the developing mid-gut. An abnormality associated with this duct failing to regress is called Meckel's diverticulum. (More? [git.htm Gastrointestinal Tract Notes] | [git2.htm Gastrointestinal Tract Abnormalities])
Wolffian duct - (= mesonephric duct, preferred terminology), A developmental duct that runs from the mesonephros to cloaca. The duct in male differentiates to form the vas deferens and in female regresses. Named after Caspar Friedrich Wolff (1733-1794), a German scientist and early embryology researcher and is said to have established the doctrine of germ layers. (More? [genital.htm Genital Notes] | Caspar Friedrich Wolff)
X chromosome - The female sex chromosome, which following sexual reproduction is inherited from each parent in females, and inherited from the mother in males. This inheritence pattern impacts upon the pattern of genetic disease. (More? [genitalX.htm X Chromosome])
Xist - The name for a non-translated RNA (18 Kb) that is associated with the inactivated X chromosome in female cells to correct for the double gene dosage, 2 copies of teh X chromosome. (More? [../MolDev/Xinact.htm Molecular Development - X Inactivation] | [genitalX.htm X Chromosome] | [week1.htm Week 1 Notes])
X inactivation - Process that occurs in all cells within females, each cell has 2 copies of the X chromosome (one from father and one from mother) one of copy of which is randomly inactivated throughout the entire body in order to maintain gene dosage. (More? [../MolDev/Xinact.htm Molecular Development - X Inactivation] | [genitalX.htm X Chromosome] | [week1.htm Week 1 Notes])
X linked - Term used to refer to genes, and genetic diseases, located on the X chromosome. Therefore more likely to be expressed in males, where there is only a single maternal X chromosome. (More? [genitalX.htm X Chromosome])
Y chromosome - The male sex chromosome which contains the sry gene producing Testis-Determining Factor required for male phenotype and can only be inherited from father. In humans the chromosome contains 200+ genes and consists of 50 million base pairs. Testis-Determining Factor (TDF; Testis-Determining Factor on Y, TDY ) is a protein transcription factor and a member of the high mobility group (HMG)-box family of DNA binding proteins. See also the transcription factor SRY-related protein, SOX9 (SRY-related high-mobility group (HMG) box 9). (More?[genitalY.htm Y Chromosome] | [../MolDev/MolDev.htm Molecular Notes] | [week1.htm Week 1 Notes] | OMIM)
yolk sac - An [index/E.htm#extraembryonic_membrane extraembryonic membrane]which is endoderm origin and covered with extraembryonic mesoderm. Yolk sac lies outside the embryo connected initially by a yolk stalk to the midgut with which it is continuous with. The endodermal lining is continuous with the endoderm of the gastrointestinal tract. In reptiles and birds, the yolk sac has a function associated with nutrition. In mammals the yolk sac acts as a source of primordial germ cells and blood cells. (More? [week2.htm Week 2 Notes] | [git.htm Gastrointestinal Tract Notes] | [heart20.htm Cardiovascular System - Blood])2010-04-12T17:17:11Search Google
Glossary Links
- Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link
Cite this page: Hill, M.A. (2024, April 23) Embryology Uterus Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Uterus_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
