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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


cell cycle G0
Cell cycle


The state of a cell that has withdrawn from the cell cycle.
(More? Week 1 | Mitosis)


The period of the cell cycle that occurs after the completion of mitosis and before the beginning of DNA replication; also called the first growth phase.
(More? Week 1 | Mitosis)


The period of the cell cycle that occurs between the completion of DNA synthesis and before the beginning of mitosis (of the next cell cycle).
(More? Week 1 | Mitosis)


A genetics term used to describe a technique for staining chromosomes during metaphase. The resulting banding pattern is seen by treating with trypsin and then staining with the dye giemsa. There are several other chromosome staining techniques, the inverse banding pattern or reverse giemsa chromosome banding, is described as R-banding.
(More? Histology - G-banding | Molecular Development - Genetics)

G-protein coupled receptor

(GPCR) Cell membrane receptor involved in many different cell signaling pathways. The common feature of this transmembrane protein is the 7 membrane spanning loop domains with an extracellular N-terminus and intracellular C-terminus.
(More? muscarinic receptor, endothelin)


An inappropriate milk production. Term is not used in relation to postnatal lactation where excess milk may be produced. Condition can occur in association with an anterior pituitary tumour producing prolactin (hyperprolactinemia).
(More? Endocrine - Pituitary Development | Normal Development - Milk)


An enzyme deficiency disorder, unable to metabolise the simple sugar galactose. The missing enzyme galactose-1-phosphate uridyl transferase metabolizes galactose in milk sugar.
(More? Prenatal Diagnosis | Neonatal Diagnosis | MedlinePlus - Galactosemia)
Galant reflex
Galant reflex

Galant reflex

(trunk incurvation reflex) Clinical term describing a primitive reflex, an involuntary response (reflex) that is present at birth and that normally disappears after 4 weeks. The reflex response occurs when the neonate is held in ventral suspension (face down) to move the hips toward the stimulated side when the back is stroked along the spinal cord. Absence of the reflex may indicate spinal cord lesion or other neurological defect. Named after Johann Sussmann Galant, a Russian neurologist.
(More? Neural Exam - Newborn reflexes - Galant | Neural System Development | Neonatal Development)


(S-type lectins) Term describing a family of soluble animal β-galactoside-binding proteins. These proteins have an affinity to β-galactosides and a specific sequence motif called lectin domain. Galectins do not contain a secretion signal, though several are externalized by non-classical secretory mechanisms and appear to regulate either cell-to-cell or cell-to-matrix interactions.
(More? limb | Molecular Development)

gall bladder

The septum transversum differentiates to form the hepatic diverticulum and the hepatic primordium, these two structures together will go on to form different components of the mature liver and gall bladder. In the adult, the gall bladder is a site of bile salt storage and concentration, to then be released into the small intestine where they act to solubilize dietary lipids by their detergent effect. Bile salts are a cholesterol derivative (breakdown product).
(More? gall bladder | liver | Gastrointestinal Tract Development)


Acronym for gut-associated lymphoid tissue.


(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 | spermatozoa | oocyte | meiosis)

gamete intrafallopian transfer

(GIFT) An in vitro fertilization surgical technique where by laparoscopy, oocytes are removed from the ovary and transferred to the uterine tube with spermatozoa. The technique was used to treat infertility.
(More? In Vitro Fertilization)


The production of either the haploid germ cells of spermatazoa (male) or eggs (female)
(More? Week 1 | spermatozoa | oocyte | meiosis)


The haploid form of a life cycle characterized by alternation of generations.
(More? Week 1 | spermatozoa | oocyte | meiosis)


Greek letter, (Γ , γ) the lower case form used in scientific literature to designate different forms/variants of a similar protein, gene, energy form or substance.
(More? Greek Symbols)

gamma radiation

(Greek letter Γ capital letter gamma; γ lower case gamma) A type of electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions which can be either mutagenic (DNA damage) or can cause serious cellular damage when absorbed by living cells.
(More? Abnormal Development - Radiation)


The anatomical and histological name given to a number (pleural of ganglion) of clusters of cell bodies. Typically identifying neurons of the peripheral nervous system some examples include: spinal ganglia (dorsal root ganglia), sympathetic ganglia, myenteric ganglia within the gastrointestinal tract wall.

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 and can generate a broad ligament cyst or vaginal cyst. Named after Hermann Treschow Gartner (1785-1827) a Danish surgeon and anatomist.
(More? genital abnormalities)

gastric transposition

Clinical term for postnatal surgery treatment for esophageal atresia involving esophageal replacement. Typically performed on neonates between day 1 to 4.
(More? Gastrointestinal Tract - Abnormalities | PMID 28658159]

gastrocoel roof plate

(GRP) A region in the early frog (Xenopus) development that is equivalent to the primitive node region (mouse, ventral node) during gastrulation and left/right axis formation. Cells in this region form a monociliated planar polarized epithelium, motile nodal cilia rotation is thought to control overlying fluid flow and establish the left/right body axis.
(More? Frog Development)

gastrointestinal tract

(GIT) The digestive tube extending from the oral cavity (mouth) to the anus. The digestive system includes the associated organs, which may also have other functions.
(More? Gastrointestinal Tract Development)


(paraomphalocele, laparoschisis, abdominoschisis, abdominal hernia) A developmental abnormality, which occurs as an abdominal wall defect associated with evisceration of the intestine (2.5 cases/10,000 births). Usually occurs as an isolated defect, defects in other organ systems have been reported in up to 35% of children. There are several theories as to the cause of this abdominal wall defect, including recently failure of the yolk sac and related vitelline structures to be incorporated into the umbilical stalk.PMID19419415 Note that the similar appearing abnormality of omphalocele involves a lack of normal return of the bowel to the abdominal cavity and position relative to the umbilical cord.
(More? Gastroschisis | Gastrointestinal Tract - Abnormalities | PMID19419415 | PMID:17230493 | PMID: 19419414 )

gastrosplenic ligament

(gastrolienal ligament, ligamentum gastrosplenicum) Structure derived from the dosal mesogastrium (mesentery) connects the spleen to the stomach as part of the greater omentum.
(More? Gastrointestinal Tract Development | Spleen Development)


(Greek, gastrula = little stomach) An early stage of an animal embryo development, occurring after blastula (blastocyst) stage in which the three germ layers have just formed by the process of gastrulation.
(More? Gastrulation | Endoderm | Mesoderm | Ectoderm | Frog Gastrula)


The process of differentiation forming a gastrula. Term means literally means "to form a gut" but is more in development, as this process converts the bilaminar embryo (epiblast/hypoblast) into the trilaminar embryo (endoderm, mesoderm, ectoderm) establishing the 3 germ layers that will form all the future tissues of the entire embryo. This process also establishes the the initial body axes.
(More? Gastrulation | Endoderm | Mesoderm | Ectoderm | Lecture - Week 3 Development)


One of the GATA-binding protein family of zinc-finger transcription factors (recognize a consensus sequence known as the 'GATA' motif) involved in many aspects of embryo development. Expressed in white adipocyte precursors prior to diifferentiation and also to have a role in regulation of skin development through lipid biosynthesis.
(More? Integumentary System Development | JCB - Skin Development | OMIM - GATA3)


One of the GATA-binding protein family of zinc-finger transcription factors (recognize a consensus sequence known as the 'GATA' motif) involved in many aspects of embryo development. GATA4 and GATA6 activity interact to regulate gene expression in the developing cardiovascular system.
(More? [Cardiovascular System Development] | PNAS - Cardivascular Development | OMIM - GATA4)

Gaucher disease

Human metabolic disorder caused by inherited deficiency of acid β-glucosidase (GCase). The acid β-glucosidase gene mutations lead to defective hydrolysis of glucosylceramide, that in turn results in the storage of glucosylceramide in various organs including; liver, spleen, bone marrow and the central nervous system. Clinically there are two major disease forms a non-neuronopathic (Type 1) and neuronopathic (Type 2 and 3).
(More? Human Abnormal Development | PMID 20047948)


Acronym for Group B Streptococcus. May also be used as an acronym for Guillain-Barre Syndrome, a neural abnormality named after the three French neurologists who originally described the condition in 1916.


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? Molecular Development - Genetics)

gene names

The official accepted nomenclature (naming) of genes to avoid confusion in terminology has been curated by different official bodies for different species. For example, human gene names by the HUGO Gene Nomenclature Committee (HGNC), worm (Caenorhabditis elegant) by Wormbase, mouse by JAX and zebrafish by ZFIN.

Gene Ontology Consortium

"The mission of the GO Consortium is to develop a comprehensive, computational model of biological systems, ranging from the molecular to the organism level, across the multiplicity of species in the tree of life."
(More? Gene Ontology Consortium | molecular)


The science of studying genes.
(More? Molecular Development - Genetics)


(Latin, genitalis = “of or belonging to generation”) The term used to describe either the external or internal male and female sexual and reproductive organs.
(More? Genital System Development)

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? Genital System Development)
genital tubercle
genital tubercle

genital tubercle

(GT) 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. The endodermally derived urethral epithelium lies within the genital tubercle and functions as an organizer by expression of sonic hedgehog (Shh). This signaling is required for initial genital tubercle formation and for ectoderm induction for urethral tube closure.
(More? Genital System Development | PMID 19906862)


(McGoldrick-Gerson study, Lapidus Schematic, Family Diagram) A clinical diagram constructed to show an individual's family relationships and medical history.
(More? Image- Genogram symbols | Genetics | Genetic Abnormalities)


The collection of all the DNA in an organism.
(More? Genetics)

genomic imprinting

Epigenetics, expression of imprinted genes is monoallelic and dependent upon the parents sex (parental imprinting), in contrast most genes (which are non-imprinted) have biallelic expression. This is an heritable change that does not alter DNA sequence. This imprinting results in a a gene or genomic domain becoming biochemically marked (for example, by DNA methylation) with information about its parental origin.
(More? Week 1)


The genes present in a particular organism or cell. In diploid cells, there are chromosome pairs each having a separate copy of every gene. In haploid cells, there is only a single copy of every gene.

germ cell

(primordial germ cell) Term used to describe the embryonic population of cells that will form either the spermatozoa (sperm) progenitor in the embryonic testes or oocyte (egg) progenitor present in the primordial follicle ovary from birth, located in the stroma of the ovary cortex beneath the tunica albuginea. In humans, these cells initially migrate during week 5-6 into the genital ridge which will later form the gonad.
(More? Genital Development | Oocyte Development | Spermatozoa Development | Lecture - Genital Development)
germ disc

germ disc

(embryonic disc) Historic term used to describe the early bilaminar and trilaminar embryonic disc that occurs during week 2 to 3 of human development, prior to folding. The term "germ" refers to this being the cellular source of the entire embryo, the term "embryonic disc" is now preferred to describe this stage of development.
(More? Carnegie stage 5 | Carnegie stage 6 | Carnegie stage 7 | Week 2 | Week 3)

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. Term originally used by Robert Remak (1815 - 1865), a German scientist and embryologist.
(More? Week 2 | Week 3 | Robert Remak)

germline cyst

(cystocyte, cyst) Term referring to the groups of interconnected cytoplasm of cells (syncytium) formed as gametogenesis is initiated in germ cells. Found in many vertebrate and invertebrate species and well characterised in the fly model, drosophila. Cyst development requires: synchronous division, a branched pattern of interconnection between cells, changes in cyst geometry, cyst polarisation, and the fusome (an organelle that is associated with cyst formation in many insects).
(More? Oocyte Development | Spermatozoa Development)

germinal epithelium

The simple cuboidal epithelium component covering surface of ovary, it is continuous with mesothelium covering mesovarium. Note that it is a historical misnomer, as it is was thought to be the site of primordial germ cell formation, but acts as a covering epithelium with no role in primordial follicle formation.
(More? Ovary Development | Oocyte Development)

Germinal Matrix-Intraventricular Haemorrhage

(GM-IVH) in preterm infants most common form (up to 20% of preterm infants, less than 32 weeks gestation) of intracranial bleeding (haemorrhage).
(More? NZ National Women's Health GM-IVH)

germinal vesicle

(GV) An oocyte nucleus development stage occurring within the ovarian follicle that is before meiosis 1 and meiosis 2. The nuclear chromatin changes can also be divided into an early decondensed phase (nucleolus not surrounded by heterochromatin) and a later chromatin condensed phase (perinucleolar rings can occur depending on species).
(More? Oocyte Development)


(Latin, germinare = to sprout) the resumption of growth by a seed.


The period of time from conception to birth. A pregnancy with multiple fetuses is referred to as a multiple gestation.

gestational age

(GA) The clinical term given in week to describe human development timed from the first day of the last menstrual period (LMP). For gestational age in assisted reproductive technology pregnancy 2 weeks are added to the fertilisation date. Age therefore differs by approximately two weeks from research materials timed from fertilisation (conceptional age), this term is generally not used clinically.
(More? Gestational Age | Timeline human development | PMID 15520122)

gestational carrier

A woman who carries an embryo that was formed from the egg of another woman; the gestational carrier is expected to return the infant to its genetic parents.

gestational sac

A fluid-filled structure that forms within the uterus early in pregnancy. In a normal pregnancy, a gestational sac contains a developing fetus.

gestational trophoblastic disease

(GTD, Gestational trophoblastic neoplasia, GTN) Term describes a number of abnormalities including complete and partial hydatiform mole, invasive mole, choriocarcinoma and placental site trophoblastic tumor (PSTT). A hydatiform mole is a tumour with "grape-like" placenta appearance without enclosed embryo formation, arises mainly from a haploid sperm fertilizing an egg without a female pronucleus.
(More? Week 1 | Week 2)

gestational diabetes

(gestational diabetes mellitus, GDM) The form of diabetes occurring during pregnancy (5-6 % of singleton pregnancies, higher in twin pregnancies), where hormones can prevent insulin from working properly. Fetal (placental) regulation of maternal glucose levels usually allows support for fetal growth. Unregulated glucose levels can lead to fetal macrosomia. The mother usually reverts after the pregnancy, though this disease can be an indication of a risk of developing Type 2 diabetes later in lifef
(More? Abnormal Development - Maternal Diabetes | Medline - Diabetes Type 2 | Endocrine - Pancreas Development)

gestational trophoblastic neoplasia

(GTN) The development of the trophoblastic cell not containing an embryo, hydatidiform mole, which can be benign or malignant. Due to the continuing presence of the trophoblastic layer, this abnormal conceptus can implant in the uterus.
(More? Week 2)


Acronym for Glial Fibrillary Acidic Protein a cytoskeletal intermediate filament protein found mainly in glial (astroglial) cells. Can be released into the serum after prenatal brain damage or by death of these cells, astrogliosis.
(More? neural abnormalities)


(Greek, leptos = thin; lenomorelin, INN) a polypeptide hormone produced in the gastrointestinal tract (stomach) and pancreas that stimulates release of growth hormone from the anterior pituitary. Hormone which probably has a role in regulating appetite and energy balance.
(More? endocrine | Meier U & Gressner AM. (2004). Endocrine regulation of energy metabolism: review of pathobiochemical and clinical chemical aspects of leptin, ghrelin, adiponectin, and resistin. Clin. Chem. , 50, 1511-25. PMID: 15265818 DOI.


Arconym for Growth Differentiation Factor 9, a member of the transforming growth factor-beta superfamily required for ovarian folliculogenesis.
(More? TGF-beta | OMIM - GDF9


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? hypothalamus‎)


(gamete intrafallopian transfer) An in vitro fertilization surgical technique where by laparoscopy, oocytes are removed from the ovary and transferred to the uterine tube with spermatozoa. The technique was used to treat infertility.
(More? ART)

glial cell

A cell within the nervous system that does not itself transmit electrical and chemical signals, but which provides metabolic and structural support for neurons. Glial cells and neurons have the same embryonic neural stem cell origin, glia generally forming after neurons are generated. There are many different types of glial cells. The Schwann cell form the glia surrounding axons in peripheral nerves.
(More? neural)


A glycoprotein secreted from different tissues and in several glycosylated forms, it is a member of the lipocalin superfamily. Glycodelin-A is released from endometrial glands (into the uterine space) under progesterone regulation. Glycodelin from the placenta has an apparent immunosuppressive activity.


Also called round-headed spermatozoa, is a human infertility syndrome caused by spermatogenesis defects leading to a malformed or absent sprematazoa acrosome. The acrosomal reaction being a key component of sperm fertilization of the egg.
(More? spermatozoa | Week 1 | OMIM - Globozoospermia)


(polar body} Historic terminology for the polar body, the exclusion body formed for the maternal additional genetic material formed during oocyte meiosis.
(More? Image polar bodies | zygote | Historic Terminology)

globus pallidus

(paleostriatum; Latin, globus pallidus = pale globe) A sub-cortical neural structure of the brain lying beside the basal ganglia. Embryonic origin is from the ventral medial ganglionic eminence and dorsal preoptic area.
(More? neural | PMID 20181579)


Clinical term describing an abnormality of the tongue position that is displaced downward or retracted. See Pierre Robin Sequence.
(More? head abnormalities)


(Greek, = larynx) the boundary between pharynx to the larynx and consists of the vocal folds and their associated intervening space.
(More? Gastrointestinal Tract Development | respiratory)


A protein hormone produced in the pancreas; a signal for the postabsorptive state; glucagon inhibits glycogen synthesis and stimulates its breakdown into glucose.


(Greek, glykos = sweet + Latin, calix = cup), also called the cell coat. A densely staining zone just out-side most eukaryotic cells.


(Greek, glykys = sweet, referring to sugar + Iyein = to loosen) A set of ten chemical reactions that is the first stage in the metabolism of glucose.


(gnathostomata) A phylogeny term describing the jawed vertebrate group, differing from all other craniates or vertebrates in having a vertically biting device, the jaws. Within this group are the Chondrichthyans (cartilaginous fishes) and the Osteicthyans (bony fishes).
(More? Tree of Life - Gnathostomata)


(goiter) The enlargement of thyroid gland due to a dietry deficiency of iodine, or thyroid hormone level abnormalities. Iodine is required to synthesise thyroid hormone which in turn is required for normal neurological development.
(More? Thyroid Development - Iodine Deficiency | thyroid)

golgi apparatus

(Golgi complex) The cytoplasmic organelle within eukaryotic cells, involved in protein processing for the cellular processes of exocytosis (secretion) and endocytosis (absorbtion). The organelle consists of a set of membrane flattened discs, usually near the nucleus. In spermatazoa, the golgi apparatus apparatus is modified to form the acrosome.


(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 | genital)

gonadal ridge

See genital ridge.


(Greek, gonos = seed; gonadotrophin, Gn) Three separate endocrine factors form the gonadotropins. Two from the anterior pituitary, luteinizing hormone (LH) and follicle stimulating hormone (FSH). The third produced by the implanting conceptus trophoblast cells and the corpus leutum in primates chorionic gonadotropin (CG), the human form is human chorionic gonadotropin (hCG). Both luteinizing hormone and follicle stimulating hormone are stimulated for release by the hypothalamus gonadotropin releasing hormone.


(Greek, gonos = seed; gonadotrophin, Gn) UK spelling for gonadotropin.

gonadotropin releasing hormone

(Greek, gonos = seed) (GnRH, GRH, gonadotrophin releasing hormone, luteinizing hormone–releasing hormone, LHRH) 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). A peptide hormone (pyroGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) processed from a 92 amino acid preprohormone.
(More? Endocrine - Hypothalamus Development | Menstrual Cycle | Week 1 | PMID 11604221)

gonadotrophin releasing hormone

(Greek, gonos = seed; gonadotrophin, Gn) UK spelling for gonadotropin releasing hormone.


(germ cell, primordial germ cell) Term used to describe the primordial germ cell population of cells that will form either the spermatozoa (sperm) progenitor in the embryonic testes or oocyte (egg) 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 ovary cortical structure containing the oocyte and the surrounding follicular cells.
(More? Genital Development | Oocyte Development | Spermatozoa Development | Lecture - Genital Development | Week 1)

Graafian follicle

(preovulatory follicle, ovulating follicle or type 8 (>1000 cells) The historic term describing most hormonally sensitive and developed antral follicle that is released by ovulation each menstrual cycle. Named after Regnier de Graaf (1641 – 1673) a Dutch anatomist and physician who described the anatomy of the uterine tube and the development of follicles in the ovary.
Ovarian Follicle Stages: primordial follicle - preantral follicle - antral follicle
(More? Ovary Development | Oocyte Development | Menstrual Cycle | Lecture - Fertilization | Lecture - Genital Development)


Term used to describe histological staining technique for characterising bacteria on the basis of dye loss/retention (Gram-negative bacteria/Gram-positive bacteria). The outer bacterial membrane prevents stain from reaching peptidoglycan layer in the periplasm, outer membrane then permeabilized and pink safranin counterstain is trapped by peptidoglycan layer.
(More? Human Abnormal Development | Bacterial Infection)


Term used to describe histological staining technique for characterising bacteria on the basis of dye retention/loss (Gram-positive bacteria/Gram-negative bacteria). A purple crystal violet stain is trapped by layer of peptidoglycan (forms outer layer of the cell).
(More? Human Abnormal Development | Bacterial Infection)

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? Ovary Development | Lecture - Genital Development)


(Latin, gravidus gravis = heavy) Clinical term referring to pregnancy, gravida the total number of pregnancies.


(Latin, gravidus gravis = heavy) The number of times a woman has been pregnant: gravida is a pregnant woman, nulligravida is a woman who has never been pregnant, primigravida is a woman who is pregnant for the first time, multigravida (secundigravida) is a woman who has been pregnant more than one time.

great vessels

Cardiovascular term describing the major blood vessels formed from the pharyngeal arch arteries: aorta, pulmonary, subclavian, and carotid arteries.
(More? Cardiovascular System Development | Head Development)

greater omentum

A peritoneal fold of splanchnic mesoderm extending from the greater curvature of the stomach and hanging ventrally down "like an apron" in the peritoneal cavity over the small intestine. It forms initially in the embryo and fetus as a loop of the dorsal mesentery, which later fuses to form a single sheet attached to the posterior body wall. The lesser omentum is a smaller ventral peritoneal fold extending from lesser curvature of the stomach to liver.
(More? Gastrointestinal Tract Development)

greater vestibular gland

(Bartholin gland) A pair of female external genital tract glands which secretes mucus to lubricate the vagina. The equivalent male gland is the Bulbourethral Gland or Cowper's Gland.
(More? Lecture - Genital Development)

Greek Symbols

These symbols are used in scientific literature to designate different forms/variants of a similar protein or gene.
(More? Greek Symbols)


A 184-amino acid protein and bone morphogenic protein (Bmp) antagonist expressed during limb development in a region anterior to the zone of polarising activity (ZPA). Recent studies suggest that it acts as a signaling intermediate between sonic hedgehog (Shh) and fibroblast growth factor (Fgf). Belongs to the BMP antagonist gene family as Cerberus (head-inducing factor) and DAN (tumor suppressor)
(More? Musculoskeletal - Limb Development | OMIM - Gremlin)


(grl) Name given to a zebrafish mutant and the related protein which generates cardiovascular system defects. The subsequent gene protein product "gridlock" is a transcription factor which has a role in determining artery/vein fate of lateral posterior mesoderm precursor cells.
(More? Cardiovascular System Development | PMID 11700560)

Growth Differentiation Factor 9

(GDF9) A member of the transforming growth factor-beta superfamily required for ovarian follicle development, F#folliculogenesis.
(More? TGF-beta | Oocyte Development | Ovary Development | Menstrual Cycle | OMIM - GDF9

growth hormone

(GH) A peptide hormone, made in the anterior pituitary, that stimulates tissue and skeletal growth. In the ovary, growth hormone also increases granulosa cell FSH-dependent E2 production.
(More? Endocrine - Pituitary Development)

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 - Hypothalamus Development)

Group B Streptococcus

(GBS) common bacteria in lower intestine of healthy adults (10 - 35%) also found in the vagina (13%) Women infected with no symptoms "colonized". This bacteria can also cause overwhelming infection and death. One of the common cause of neonatal bacterial infections and immunoglobulin G (IgG) antibodies against capsular polysaccharides of GBS serotypes Ia, II, and III have been identified in cord sera.

growing pains

An intermittent aches or pains in legs that occur in the evening or at night occuring in children aged 3-12 years and may also occur during puberty growth.
(More? Postnatal Development)


(guanine triphosphate) one of the 4 types (ATCG) of nucleotides that make up DNA. Base pairs with cytosine by 3 hydrogen bonds.
(More? DNA Notes)


A mesenchymal structure occurring associated with gonad development and involved in testes descent. Two factors, insulin-like peptide hormone 3 (INSL3) and androgen, have been shown to be involved with gubernaculum development. Insulin-like peptide 3 (INSL3) hormone receptor is RXFP20.
Human gubernaculum development: 8-12 weeks - mesonephric fold at or near the gonad; 20-25 weeks - connected to the testis or uterus. PMID: 18661576
(More? Lecture - Genital Development | PMID 11008363 | PMID 18661576)

Guillain-Barre Syndrome

(Guillain-Barré syndrome, GBS) An autoimmune disease that attacks the peripheral nervous system. Named after the three French neurologists who originally described the condition in 1916.
(More? NIH)

gut-associated lymphoid tissue

(GALT) Immune system lymphoid tissues associated with the gastrointestinal tract intestinal mucosa including: cryptopatches, isolated lymphoid follicles, Peyer’s patches and caecal and colonic patches.
(More? Immune System Development | Gastrointestinal Tract Development)

Guthrie test

A newborn blood screening test carried out for a variety of known genetic disorders. Blood is collected using a heel prick and spotted onto a test sheet to dry for later testing.
(More? Guthrie test | Dr Robert Guthrie | Neonatal Diagnosis)


Acronym for Germinal Vesicle BreakDown, occurs in the oocyte and indicates the onset of meiosis I.
(More? Meiosis | Image - canine oocyte development)


(Greek, gyne = woman) doctor specializing in treating diseases of female reproductive organs.


(Greek, gyne = woman, mastos = breast) is the excessive development of the male breast, which can occur transiently in puberty or due to other (hormonal) abnormalities, such as excess aromatase.
(More? Integumentary System - Mammary Gland Development)


(pl. gyri) Term referring to the brain surface anatomy forming a ridge on the cerebral cortex surface. The corresponding surface infold is a sulcus.
(More? Neural System Development | Lecture - Neural Development)

Glossary Comments

Use this page to access brief definitions of specific embryology terms. Additional information can be accessed from links listed at the end of each definition. Glossary from the UNSW Embryology program compiled and written by Dr Mark Hill. Reference material used in preparing this glossary list includes: texts listed on page 1 "Reading" of each notes section, Department of Anatomy Publications, WWW resources from NCBI, NIH, OMIM, NHMRC (Australia), AMA (USA), Office of Rare Diseases (USA), PubMed Medline Dictionaries, MSDS, Merck Manual home edn. and WHO ART terminology (2009).

These notes are for Educational Purposes Only Please email Dr Mark Hill if you wish to make a comment about this current project.

Glossary Links

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Cite this page: Hill, M.A. (2024, May 25) Embryology G. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/G

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