Beginnings, Growth and DevelopmentThis section gives a very brief overview of genital postnatal changes that occur in neonatal, childhood and through to puberty. These topics, particularly puberty, will be revisited in detail in other parts of your course. For sexual development at puberty, we will use resources available online from Endocrinology: An Integrated Approach (NCBI Bookshelf).
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Female tract abnormalities tend to be rarer and when they do occur are also more difficult to detect. The newborn male is more likely to have abnormalities that are easily detected asociated with fusion of the urogenital folds, undescended testes or hernia. Genital abnormalities will be discussed in detail on the next page. |
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In the female ovary, human germ cell numbers decrease with age, peaking at about 7 million (occuring in early fetal development) and then decreasing by apopotic cell death. At puberty there remain only about 400,000 and only about 10% of these will be released through reproductive life.
(Based on data from: Hassold, etal., Environ Mol Mutagen 1996. 28: 167-175) |
Links: Oogenesis
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Latin, pubertas = "adulthood" In the teen years the endocrine changes that signal sexual development trigger changes in primary sex organs and the development of secondary sexual characteristics. Hypothalamic expression of gonadotropin releasing hormone (GnRH) is a known puberty trigger. Recent research suggests that an earlier signal could come from increased neuronal and hypothalamic expression of a peptide family (kisspeptins) and their receptor (G protein-coupled receptor GPR54) in the hypothalamus. GnRH then signals the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to start sexual development. Puberty can occur over a broad range of time and differently for each sex:
Early onset of puberty (precocious) occurs more frequently in girls than boys, in contrast late onset (delayed) occurs more frquently in boys than girls. |
The physical characteristics that can be generally measured are: genital stage, pubic hair, axillary hair, menarche, breast, voice change and facial hair. In 1976, Tanner and Whitehouse established a series of descriptive stages for primary and secondary sexual characteristic development at puberty. Study the Tanner stages comparing the male and female physiological changes.
Links: Normal Development - Puberty | Integumentary Development - Mammary Glands | Australia HealthInsite - Puberty
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In females, menarche (the first menstruation or a period) usually occurs after the other secondary sex characteristics, and will continue until menopause (permanent cessation of reproductive fertility). The diagram shows the hormonal regulation pathway from the brain to the ovary and subsequent impact on uterine changes during the menstral cycle.
A similar endocrine axis is also found for regulation of the male gonad. (Image: NIAAA Emanuele, M.A. etal) |
Study the case reports on both early (precocious) sexual development and late (delayed) puberty.
Then read the assciated notes on Precocious sexual development and Delayed puberty.
What are the definitions and causes of delayed puberty? Note also the comments about premature adrenarche which is not as serious as precocious sexual development.
Now read about some general puberty issues, and then male and female specific puberty issues.
General: Acne, hair growth and hirsutism
Female: The breast - premature development, hypoplasia and gynecomastia | The ovary - folliculogenesis and oogenesis
Male: Spermatogenesis | Erection and ejaculation | Control of testicular function |
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Link to next page in this Practical - Abnormalities This next page shows a selection of abnormalities of sexual differentiation. |
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.
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 |
abdomen - trunk between diaphragm and pelvis.
AC - Acronym for Abdominal Circumference.
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? 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 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? Endocrine Notes - Adrenal Gland)
adrenal virilism - Abnormality that leads to the development of male secondary sexual characteristics in women with excessive adrenal gland activity. (More? Endocrine Notes)
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.
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? Inner Ear | 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? Genital System - Male)
anovulation - The absence of ovulation, failure for an oocyte (egg) to be released from the ovary. (More? Week 1 Notes)
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? 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? 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? 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 - An ovarian follicle that fails to mature and degenerates. Also called "atresia" referring to the process of degeneration of the ovarian follicle. At any one time the majority of follicles are destined not to complete maturation and degeneration can occur at any stage (from type 4-7). (More? Week 1 Notes | Ovary Notes)
autosomal - The term decribing all the chromosomes that contribute to a cell's genetic material, except for the sex chromosomes X, Y. (More? 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 Notes)
birth - (parturition) Term describing the pysiological process of offspring (child) being born. (More? 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? 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? 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? 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.
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 Notes)
congenital - Already present at birth, often used to describe defects present at birth, congenital defects. (More? Abnormal Development)
corticosteroid - A steroidal hormone produced by the adrenal cortex. (More? 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? Abnormal Development - Environmental)
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? Urogenital Notes | 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? Urogenital Notes | 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 → straight tubule → rete testis → ductuli efferentes → ductus epididymidis → ductus deferens) (More? Spermatogenesis | Genital - Male | 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? Genital - Male | Genital 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? UNSW Embryology | 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 Notes)
endocrine disruptors - Term used to describe environmental chemicals that interfere with hormone function. Three main forms of interference: Mimic (effects of natural hormone), Block (binding of hormone to receptor or synthesis), Interfere (with hormone transport or elimination). (More? Endocrine Abnormalities)
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 Notes)
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? Urogenital Notes | 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? Human Menstrual Cycle)
fallopian tube - (see uterine tube, uterine horn, oviducts) A pair of tubular structures designed to transport the oocyte (egg) from the ovary to the uterus body, named after Gabriel Fallopius (1523-1562), an anatomists and physician.
Fetal Origins Hypothesis - (fetal programming hypothesis, Barker Hypothesis) Originally called the Barker Hypothesis, which began as statistical analysis carried out by Barker in the UK, of low birth weight data (early 1900's) and proposes in utero influences cause permanent changes in embryo/fetus, low birth weight, predisposition to chronic disease in adult life. (More? Fetal Origins Hypothesis | Search Pubmed - fetal origins hypothesis)
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? Week 1 Notes)
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? Week 1 - Oogenesis | Human Menstrual Cycle | Genital System - Female)
follicle atresia - The degeneration of the developing ovarian follicle, which can occur at any stage of follicular development. Many developing follicles undergo this process in each menstrual cycle. (More? Week 1 - Oogenesis | Human Menstrual Cycle | 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? Week 1 - Oogenesis | Human Menstrual Cycle | 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 development within the ovary. The follicle is the structure developing within the ovary that includes the oocyte (egg) and surrounding support cells. (More? Week 1 - Oogenesis | Human Menstrual Cycle | 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? Week 1 Notes)
gameteogenesis - The production of either the haploid germ cells of spermatazoa (male) or eggs (female) (More? 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? 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 Notes)
genitalia - (Latin, genitalia = ) The term used to describe either the external or internal male and female sexual and reproductive organs. (More? Urogenital Notes)
genital ridge - (= gonadal ridge) The thickened epithelial/mesenchymal region adjacent and medial too the mesonephros. Primordial sex cells migrate into this region to form the indifferent gonad. These undifferentiated gonads have a cortex and a medulla. Female XX chromosome complex, cortex differentiates into an ovary, and medulla regresses. Male XY complex, medulla differentiates into a testis and cortex regresses. (More? Urogenital Notes)
genome - The collection of all the DNA in an organism. (More? 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? Week 2 Notes 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? 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? Week 1 Notes)
gonadotrophin releasing hormone - (Greek, gonos = seed) (GnRH) Hormone released from hypothalamus that stimulates pituitary gonadotropin synthesis and secretion (luteinizing hormone, LH and 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? 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, membrana granulosa sits on the follicular basal lamina and lines the antrum as a stratified epithelium. The cumulus oophorus is a column of granulosa cells that attaches the oocyte to the follicle wall. The 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? Week 1 - Oogenesis | Corpus luteum)
growth hormone - (GH) A peptide hormone, made in the anterior pituitary, that stimulates tissue and skeletal growth. (More? 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? Endocrine Notes - Hypothalamus)
hCG - An acronym for the hormone 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.
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 Notes)
hydronephrosis - (congenital hydronephrosis, Greek, hydro = water) A kidney abnormality due to partial or complete obstruction at the pelvi-ureteric junction. This leads to a grossly dilated renal pelvis causing extensive renal damage before birth. This abnormality may be familial, may be lateral, and is most commonly an intrinsic defect in the wall of the ureter (structural or functional). The less severe cases may be salvaged by reconstruction of the pelvi-ureteric junction. (More? Urogenital Abnormalities)
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? Genital Abnormalities - Hypospadia | Genital Notes)
ICSH - acronym for Interstitial Cell Stimulating Hormone an anterior pituitary hormone. (More? 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? Genital System - Male | Genital Notes - Gonadal Descent)
interstitial cell - (Leydig cell) Alternative name for Leydig cell found within the male gonad (testis). A cell that is involved in androgen (testosterone) production. (More? Genital System - Male | 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? Endocrine Development - Gonads | Genital System - Male)
intrauterine - Term means lying within the uterus.
karyotype - (Greek, karyon = kernel or nucleus + typos = stamp) Term used to describe the chromosomal (genetic) makeup (complement) of a cell. (More? Week 1 Notes | Genetic Abnormalities)
kidney - In humans the metanephros forms the final adult kidney. An excretory organ which also has endocrine functions. (More? Urogenital Notes)
lactation - (Latin lactans = suckling) production of milk through action of prolactin and other hormones on breast tissue. Therefore associated mainly with mammals. (More? Normal Development - Milk | Integumentary Development - Mammary Glands)
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 Notes | Urogenital Notes)
ligamentum teres - (ligamentum teres uteri, Hunter's ligament) The round ligament of 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? Human Menstrual Cycle | 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? Human Menstrual Cycle | 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 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? Week 1 Notes)
mammary gland - A specialised modified secretory gland producing milk in female mammals for neonatal nutrition. Note that milk production and neonatal nutrition through milk, define us as mammals. (More? Integumentary Development - Mammary Glands)
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 → straight tubule → rete testis → ductuli efferentes → ductus epididymidis → ductus deferens) (More? 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 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.)
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 Notes)
mesorchium - A peritoneal fold attaching testes to the mesonephros during development. (More? Genital Notes)
mesovarium - The mesentry of the ovary formed from a fold of the broad ligament that attaches the ovary. (More? Week 1 Notes)
metanephros - The adult kidney, third stage of mammalian kidney (pro-, meso-, meta-) development within the intermediate mesoderm. (More? Urogenital Notes)
Müllerian Duct - (paramesonephric duct) An embryonic paired duct system that will form the epithelial lining of female reproductive organs: utererine tube, uterus, upper vaginal canal. This duct system degenerate in male gonadal development. Named after Johannes Peter Müller (1801-1858) a German scientist. (More? Uterus Development | Genital System - Female | X chromosome | Human Menstrual Cycle | 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? Uterus Development | Genital System - Female | X chromosome | Human Menstrual Cycle | 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? Male | OMIM - AMH)
Neisseria gonorrhoeae - A gram-negative bacteria which causes the disease Gonorrhea, which is a sexually transmitted disease (STD). (More? Abnormal Development - Bacterial)
nephron - (Greek, nephros = kidney) The functional unit of the kidney. Urogenital Notes
nephros - (Greek, nephros = kidney) Term used to describe features associated with the kidney. (pronephros, mesonephros, metanephros, nephric, nephron, nephroblastoma) Urogenital Notes
oviduct - (uterine horn, fallopian tube, oviduct, salpinx) see uterine tube. A pair of tubular structures designed to transport the oocyte (egg) from the ovary to the uterus body. (More? Week 1 - Oogenesis | Week 1 Notes | Blue Histology - Female Reproductive System)
ovulation - The term used to describe the process of the mature follicle releasing the oocyte or ovum (and support cells) from the ovary surface into the peritoneal cavity. In humans, generally a single oocyte is released from a cohort of several maturing follicles. More than one follicle may be released (superovulation) following reproductive therapeutic treatment. (More? Week 1 - Oogenesis | Week 1 Notes)
paramesonephric duct - (also called Mullerian duct) (Greek, para = "beside") The paired ducts that lie beside the mesonephric ducts, that will differentiate in the female embryo to form the female internal genital tract (uterine tubes, uterus, upper vaginal canal). (More? 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? Respiratory Notes)
peritoneal cavity - The anatomical body cavity in which the lower body organs lie: intestines, liver, bladder, 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? Coelomic Cavity Notes | 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? Week 1 - Spermatogenesis)
PGC - acronym for Primordial Germ Cell, the embryonic cell that will form eventually either egg or sperm cell. (More? Genital Notes | primordial germ cell movies)
Polycystic ovary syndrome - (PCOS) or Stein-Leventhal syndrome (1930s researchers) a metabolic syndrome with many other symptoms, ovarian cysts arise through incomplete follicular development or failure of ovulation. (More? Urogenital Abnormalities)
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 uterus and rectum.
preantral 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? Week 1 - Oogenesis)
primary 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? 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? 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. (More? Week 1 Notes)
processus vaginalis - A transient communicating channel in testes development between tunica vaginalis and peritoneal cavity. (More? 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? Human Menstrual Cycle)
progestins - these compounds are synthetically produced progestogens used clinically and experimentally. (More? 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 (PRLH, prolactin-releasing peptide). Recently been shown to to mimic in pregnancy effects of increased maternal myelination processes (oligodendrocyte precursor proliferation). (More? Endocrine Development - Pituitary | 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? Endocrine Development - Hypothalamus | OMIM - PRLH)
pseudohermaphrodite - Term used for having both male and female reproductive organs, occurs in male and female forms (with an additional a True Hermaphrodite form)
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? Endocrine Notes - Gonad | Puberty Notes)
raphé - Anatomical line of fusion of the urogenital folds lying along the urethra and scrotum in male external genitalia. (More? Urogenital Notes)
rectouterine pouch - (Pouch of Douglas or rectovaginal) Anatomical description of the female peritoneal cavity lying between the back wall of the uterus and rectum.
renal - (Latin, renes = kidney) Term used in relation to the kidney and associated structures (renal pelvis, renal artery) (More? Urogenital Notes)
rete ovarii - A group of epithelial tubules located at the hilum of the ovary possibly mesonephric origin. (More? 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 → straight tubule → rete testis → ductuli efferentes → ductus epididymidis → ductus deferens) (More? Spermatogenesis | Urogenital Notes)
SDI - Sexually Transmitted Infection, this term replaces the older term Sexually Transmitted Disease, any infection that can be transmitted by sex between partners.
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? Embryo Stages | Human Fetal Period | 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? Urogenital Notes | Enrico Sertoli | UWA Blue Histology - Male Reproductive System)
sperm - The male haploid reproductive cell, often used generically (and incorrectly) to describe these cells and the fluid of the ejaculate. Term is a shortened form of scientifically correct term spermatazoa. (More? Week 1 - Spermatogenesis)
spermatazoa - The male haploid reproductive cell, produced by meiosis in the testis (male gonad). (More? Week 1 - Spermatogenesis)
spermatogenesis - (Greek, genesis = origin, creation, generation) The term used to describe the process of diploid spermatagonia division and differentiation to form haploid spermatazoa within the testis (male gonad). The process includes the following cellular changes: meiosis, reoorganization of DNA, reduction in DNA content, reorganization of cellular organelles, morphological changes (cell shape). The final process of change in cell shape is also called spermiogenesis. (More? Week 1 - Spermatogenesis)
spermiogenesis - (Greek, genesis = origin, creation, generation) The term used to describe the process of diploid spermatagonia division and differentiation to form haploid spermatazoa within the testis (male gonad). The process includes the following cellular changes: meiosis, reoorganization of DNA, reduction in DNA content, reorganization of cellular organelles, morphological changes (cell shape). The final process of change in cell shape is also called spermiogenesis. (More? Week 1 - Spermatogenesis)
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? 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? Week 1 - Spermatogenesis)
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? Molecular Notes | 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 → straight tubule → rete testis → ductuli efferentes → ductus epididymidis → ductus deferens) (More? 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? Week 1 Notes)
syphilis - disease caused by the bacterium Treponema pallidum, a spirochete with a relatively small genome and requires a host to survive. First recognized in the 15th century in Europe, it can kill early fetuses or produce congenital deafness in older fetuses. (More? Abnormal Development - Bacterial Infection)
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? 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? 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? Molecular Notes | 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? Week 1 Notes - Oogenesis | 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? Week 1 Notes - Oogenesis | Urogenital Notes)
trimegestone - A synthetic progesterone potentially used in postmenopausal women (with an intact 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? Human Menstrual Cycle)
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? 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 → straight tubule → rete testis → ductuli efferentes → ductus epididymidis → ductus deferens) (More? 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? Week 1 Notes)
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? 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? Urogenital Notes)
urinary - Term used to describe all components of the kidney system including the bladder, ureters and urethra. (More? 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? 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? Urogenital Notes)
URSMS - An acronym for urorectal septum malformation sequence, clinically describing abnormalities of the urorectal septum (URS) and urogenital organs. (More? Urogenital Abnormalities | Urogenital Notes)
urinary bladder - muscular sac for the storage of urine. (More? Urogenital Notes)
uterine horn - (fallopian tube, oviduct, salpinx) see uterine tube.
uterine peristalsis - rhythmic muscular contraction of the uterus which occurs during the menstrual cycle, maximally just before ovulation, in the non-pregnant uterus. (More? Human Menstrual Cycle | Genital System - Female Uterus | 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 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? Human Menstrual Cycle | Genital System - Female Uterus | Urogenital Notes)
uterus - The female internal genital (reproductive) tract forming a hollow muscular walled organ, embryonically derived from the 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? Genital System - Female Uterus | Human Menstrual Cycle | Genital Notes)
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. (More? Genital System - Female Uterus)
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? Gastrointestinal Tract Notes | Gastrointestinal Tract Abnormalities)
witches' milk - Historic common term used to describe the postnatal effects of an estrogen increase on the neonatal breast, which leads to aberrant milk production. This increase is probably from loss of the negative feedback effects of steroids from the placenta. (More?| Postnatal Development | Placenta Notes)
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 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? 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? Molecular Development - X Inactivation | X Chromosome | 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? Molecular Development - X Inactivation | X Chromosome | 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? 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? Y Chromosome | Molecular Notes | Week 1 Notes | OMIM)
yolk sac - An extraembryonic membranewhich 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? Week 2 Notes | Gastrointestinal Tract Notes | Cardiovascular System - Blood)
zygote intrafallopian transfer - (ZIFT) A procedure in which eggs are collected from a woman's ovaries and fertilized outside her body. A laparoscope is then used to assist in placing the resulting zygote (fertilized egg) into the woman's uterine (fallopian) tube through small incisions in her abdomen. (More? Week 1 Notes - In Vitro Fertilization)
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