D

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 | Original D

Dact1

(Dapper, Antagonist of Beta-Catenin 1) An intracellular protein that binds the membrane protein Vangl2, expressed at the primitive streak epithelial–mesenchymal transition region. Mutations of this gene in mouse (Frodo mouse or Dapper Xenopus) mimic human malformations in the spine, genitourinary system and distal digestive tract.

(More? OMIM Dapper)

dactyly

(Greek, daktulos = finger or digit) used as a siffix with words describing limb abnormalities associated with either fingers on the hand or toes on the foot. For example, polydactyly is an abnormality resulting in additional fingers or toes.

(More? Limb Abnormalities)

dally-like

(Dlp) A heparan sulfate proteoglycan (HSPG) protein found in Drosophila that is required for inhibition of the hedgehog (Hh) signaling pathway. A member of the glypican family of consists of six unique polypeptides in mammals and is characterized by an N-terminal globular domain with 14 conserved cysteine residues.

(More? PMID: 20231458)

damaged DNA-binding protein

(DDB) two proteins (DDB1 and DDB2) that form a complex which recognizes ultraviolet-damaged (UV) DNA and begins repair process (nucleotide excision repair, NER). This complex has been shown to be required for (mouse) epidemis and hair follicle development.

(More? Skin Notes | OMIM - DDB1 DDB2 | PMID: 17301228)

Dandy-Walker malformation

(DWM) The most common cerebellum development malformation in humans. Recently found to be associated with FOXC1, which leads to cerebellar vermis hypoplasia (CVH) and also affects eye development and glaucoma.

(More? Neural Abnormalities | Neural Notes)

DAX1

Acronym for "D"osage sensitive sex reversal (DSS), "A"drenal hypoplasia congenita (AHC) critical region on the "X" chromosome, gene "1" , (gene NR0B1) is a nuclear hormone receptor involved in female ovary development.

(More? Urogenital Notes | OMIM Entry DAX1)

DAZL

Acronym for DAZ-like due to homology to DAZ (Deleted in AZoospermia), a gene on the long arm of the Y chromosome that is frequently deleted in infertile men with nonobstructive azoospermia.

(More? Spermatozoa Development | OMIM Entry DAZL)

Deaf-1

Acronym for "D"eformed "e"pidermal "a"utoregulatory "f"actor-"1", a transcription factor that regulates epithelial cell proliferation and side-branching in mammary gland development. A small Rho-like GTPase (Rac3) has been identified as a potential target of Deaf-1 in mouse mammary epithelial cells. Also expressed in central nervous system, dorsal root ganglia, submandibular gland, epidermis and embryo mammary placodes.

(More? Integumentary Development - Mammary Glands | OMIM Entry Deaf-1 | PMID: 18826651)

DDB

Acronym for damaged DNA-binding protein complex. This complex, consisting of two proteins DDB1 and DDB2, recognizes ultraviolet-damaged (UV) DNA and begins repair process (nucleotide excision repair, NER). Required for (mouse) epidemis and hair follicle development.

(More? damaged DNA-binding protein | Skin Notes)

decidua

(Latin, decidua = a falling off) The term given to the uterine endometrium following implantation and signaling which transforms the uterine stromal cells (fibroblast-like).

(More? Placenta Development | Week 2 | Menstrual Cycle | Uterus Development)

decidua basalis

The term given to the uterine endometrium at the site of implantation where signaling transforms the uterine stromal cells (fibroblast-like) into decidual cells. This forms the maternal component of the placenta, the decidualization process gradually spreads through the remainder of the uterus, forming the decidua parietalis.

(More? Placenta Development | Week 2)

decidua basalis reaction

Term describing the maternal endometrial changes that occur initially at the site of, and following, blastocyst implantation. Seen as a deposition of glycogen, fibrin and proliferation of blood vessels. See also decidualization.

(More? Placenta Development | Week 2)

decidua capsularis

The term given to the uterine endometrium which has been converted to decidua surrounding the conceptus on the smooth chorion side.

(More? Placenta Development | Week 2 | Endocrine System Development)

decidua parietalis

The term given to the remainder of the uterine endometrium, away from the site of implantation, that gradually becomes comverted to decidua.

(More? Placenta Development | Week 2 | Endocrine System Development)

decidual cell

The uterine stromal cells (fibroblast-like) that differentiate in response to both steroid hormones (progesterone) and embryonic signals. These cells then alter uterine environment to support further embryonic development as well as producing cytokines related to prolactin (PRL) and have an innate immune function.

(More? Placenta Development | Week 2 | Endocrine System Development)

decidualization

The process by which uterine stromal cells differentiate in response to both steroid hormones and embryonic signals into large epitheliod decidual cells. This process is essential for the progress of implantation and establishing fetal-maternal communication.

(More? Placenta Development | Week 2)

deiodinase

A group of enzymes that can modify the thyroid prohormone secreted by the thyroid gland either activating (deiodinase 2) or deactivating (deiodinase 3) thyroid hormone. Their role is thought to regulate the amount of active hormone available locally in a tissue.

(More? Thyroid_Development)

deiodinase 2

(Dio2) A deiodinating enzyme that activates thyroid hormone by clipping the 5'-iodine off of the T4 prohormone to create T3, which is the preferred ligand for thyroid receptors. The enzyme has 5'- outer ring (5'-) catalytic activity. Has a role in regulating the amount of active hormone available locally in a tissue.

(More? Thyroid_Development)

deiodinase 3

(Dio3) A deiodinating enzyme that inactivates thyroid hormone by removing the 5-iodine from either the T4 prohormone or the T3 active hormone. The enzyme has 5- inner ring (5-) catalytic activity. Has a role in regulating the amount of active hormone available locally in a tissue.

(More? Thyroid_Development)

delayed puberty

(Latin, pubertas = adulthood) An abnormal timing of puberty. Determined in boys by a lack of increase in testicular volume by the age of 14 years. In girls, no breast development by the age of 13.5 years and a lack of menstruation by the age of 16 years. There can also be a "pubertal arrest" where there is no progress in puberty over 2 year period.

(More? Puberty Development | Genital System Development | Ovary Development | Menstrual Cycle)

delta cell

Cells located within pancreas endocrine islets that secretes somatostatin.

(More? Endocrine Development - Pancreas | Endocrine Notes | Gastrointestinal Notes)

Delta-like ligand

(Dll) one of two (Delta and Serrate family) plasma membrane (transmembrane) ligands for the Notch family of receptors. Vasular endothelial growth factor (VEGF) induces one form (Dll4) to acting in negative feedback regulatoion to prevent excessive blood vessel formation

(More? Cardiovasular - Blood Vessel | Molecular Development- Vascular Endothelial Growth Factor | OMIM - Dll4)

Delta-like ligand (Dll) 4

Delta-like ligand (Dll) 4, a transmembrane ligand for the Notch family of receptors, ... Dll4 is induced by VEGF as a negative feedback regulator and acts to prevent overexuberant angiogenic sprouting

dendrite

A thin cellular process found in neurons that bring signals towards the neuron's cell body (soma).

(More? Neural Notes)

dentin

The bone-like material in body of tooth, lacks osteocytes.

dentin phosphophoryn

(DPP) is part of dentin sialophosphoprotein (DSPP) synthesized in both mesenchyme and epithelium, involved in two developmental processes: epithelial-mesenchymal interactions and branching morphogenesis.

dermatoglyphic

The line patterns (ridges) on the skin found on the palms of the hands (finger and palm prints) and soles of the feet.

(More? Skin Notes)

dermatome

The early embryonic dorsal portion of the somite that will contribute the dermis and hypodermis of the skin. Note in the adult, this term is used to the skin sensory region innervated by a single spinal (nerve) segment.

Development: mesoderm - paraxial mesoderm - somite - dermomyotome - dermatome - dermis

(More? Somitogenesis | Musculoskeletal System Development | Integumentary System Development | Neural System Development)

dermomyotome

Early embryonic dorsolateral half of the somite that will later divide to form both the dermatome and myotome. The dermatome will contribute the dermis and hypodermis of the skin. The myotome will contribute the skeletal muscle of muscoloskeletal system.

Development sequence: mesoderm to paraxial mesoderm to somite to "dermomyotome" then dermatome and myotome

(More? Somitogenesis | Musculoskeletal System Development | Integumentary System Development)

DES

Diethyl stilbestrol or diethylstilbetrol, a drug prescribed to women from 1938-1971 to prevent miscarriage in high-risk pregnancies. Acts as a potent estrogen (mimics natural hormone) and therefore a potential endocrine disruptor. Female fetus, increased risk abnormal reproductive tract and cancer. Male fetus, abnormal genitalia. Banned by USA FDA in 1979 as a teratogen, previously used as livestock growth promoter.

(More? Abnormal Development)

Descemet's Membrane

Develops from corneal stroma and ectoderm, a specialized basement membrane of the endothelial cells which lies between the corneal stroma and the endothelial layer of the cornea. Named after the French physician Jean Descemet (1732-1810).

(More? Sensory - Vision Development)

DET

Acronym for Double-Embryo Transfers, where two embryos transferred when women undergo in vitro fertilization compared to single-embryo transfer (SET).

(More? Week 1 - In Vitro Fertilization)

detrusor muscle

The smooth muscle forming 3 layers surrounding the urinary bladder required for emptying, urination, following internal urethral orifice opening.

(More? Renal System Development | Lecture - Renal Development)

developmental dysplasia of the hip

(DHH, congenital dislocated hip, congenital hip dislocation, congenital hip dysplasia) Term describes a spectrum of musculoskeletal disorders of hip instability due either to the femoral head being able to move outside the acetabulum (luxation or dislocation), or abnormally within the acetabulum (subluxation or partial dislocation). This includes presentation following a normal examination of the hips in the newborn period (Ortolani and Barlow tests). When detected can be managed with splinting (Denis-Browne splint) allows the hip joint to develop normally and does not require surgery. If undetected and left untreated, the hip joint develops abnormally and surgical reduction is required.

(More? Musculoskeletal System Development)

diabetes insipidus

The disorder is related to the hormone antidiuretic hormone (ADH, also called vasopressin) its synthesis, secretion, receptors and signaling pathway. In diabetes insipidus there is an excretion of large amounts (up to 30 litres/day) of a watery urine and an unremitting thirst.

(More? Kidney Abnormalities - Diabetes Insipidus)

diabetes mellitus

A disease due to inadequate regulation of blood glucose usually by altered production of insulin by the pancreas. There are three main types of diabetes: Type 1 (Insulin-Dependent Diabetes Mellitus), Type 2 and gestational diabetes.

(More? Endocrine- Pancreas | Maternal Diabetes)

Diabetes Type 1

(Insulin-Dependent Diabetes Mellitus (IDDM), juvenile onset diabetes) The disease is due to the pancreas not making insulin. It can occur at any age, though it usually arises in childhood or youth, hence juvenile onset diabetes. An autoimmune disease progressive destruction of the insulin-producing beta cells in the pancreatic islets. Has both a genetic and environmental component to the disease development.

(More? Endocrine- Pancreas | Maternal Diabetes | Medline - Diabetes Type 1)

Diabetes Type 2

The most common (80%) form of diabetes. The disease due to noninsulin-dependent diabetes, where body becomes resistant to insulin a life-long disease marked by high levels of sugar in the blood.

(More? Endocrine- Pancreas | Maternal Diabetes | Medline - Diabetes Type 2)

diamniotic

A twinning term, where the twins have two amniotic sacs, which can occur in both early and late monozygotic twinning. In a monozygotic twinning event (one fertilised egg and a single spermatazoa, form a single zygote) which occurs early (within 2 days of fertilization) where each embryo then develops separately its own chorionic sac (placenta) and amnionic sacs (dichorionic diamniotic). Later splitting (more than 2 days after fertilization) may result in a shared placenta and only duplication of the embryonic amnionic sacs (monochorionic diamniotic twins).

(More? Monozygotic Twinning | Twinning | Week 1 Twinning)

diaphragm

A general term for a membranous sheet. In anatomy, describes the muscular sheet separating chest from abdomen with several different embryonic origins. Regular contraction of the diaphragm is required in respiration. The diaphragm forms initially at the lower end of the pleuroperitoneal canal.

Embryonic origins: transverse septum (septum transversum) - tendon of the diaphragm, 3rd to 5th somite pairs - musculature of diaphragm, ventral pleural sac - connective tissue, mesentry of oesophagus - connective tissue around oesophasus and inferior vena cava, and pleuroperitoneal membranes - connective tissue around central tendon.

(More? Respiratory System Development | Musculoskeletal System Development | Respiratory Development - Diaphragm | Respiratory Notes | Musculoskeletal Notes)

diaphysis

An anatomical bone term describing the shaft of long bones.

(More? Musculoskeletal System Development | Musculoskeletal Notes - Bone)

diastema

A toothless region found in mice between the incisor and the first molar. Thought to result from murine evolutionary loss of incisor, canine, and premolars.

(More? Mouse Notes)

Dicer

A small (21 nucleotide) regulatory RNA required in RNA interference and small temporal RNA (stRNA) pathways to produce the active small RNA component that represses gene expression.

(More? Cartilage Notes | Molecular Development | OMIM - DICER | Pubmed Review)

dichorionic

A twinning term, in a monozygotic twinning event (one fertilised egg and a single spermatazoa, form a single zygote) which occurs early (within 2 days of fertilization) where each embryo then develops separately its own chorionic sac (placenta) and amnionic sacs (dichorionic diamniotic). Later splitting (more than 2 days after fertilization) may result in a shared placenta and only duplication of the embryonic amnionic sacs (monochorionic diamniotic twins).

(More? Abnormal Development - Twinning)

dielectrophoresis

(DEP) Term describing the response of the induced dipole moments of particles due to the application of an external non-uniform electric field. This technique has been suggested as an alternative assay, to morphologic parameters, to select animal embryos for transfer. In the mouse preimplantation selection the embryo's light-induced dielectrophoresis response was found to be highly correlated with its developmental stage.

(More? In Vitro Fertilization | Mouse Development | PMID20405021)

diencephalon

(encephalon = brain) the embryonic neural tube region that will form the thalmus, hypothalmus and other nuclei in the adult brain. The diencephalon is the second most anterior of the 5 secondary brain vesicles formed from division of the prosencephalon (forebrain) primary brain vesicle (there are 3 primary brain vesicles). It is at the level of the diencephalon that the optic stalks (optic nerve) extends from the brain. The diencephalon lumen (cavity of the neural tube) will form the third ventricles.

Secondary brain vesicles: telencephalon - diencephalon - mesencephalon - metencephalon - myelencephalon

(More? Neural System Development | Ventricular Development)

diestrus

In most female mammals, the last stage in the estrous cycle immediately before the next cycle proestrus characterized by a functional corpus luteum and an increase in the blood concentration of prosgesterone.

Estrous cycle stages: proestrus - estrus - metestrus - diestrus

(More? Estrous Cycle | Mouse Estrous Cycle)

differentiation

The process of development of specific cell types from stem cells by gene activation and repression.

diffusion

(Latin, diffundere = "to pour out") Random movements that lead to a uniform distribution of molecules both within a solution and on the two sides of a membrane.

diffusion tensor imaging

(DTI) A newly developed form of magnetic resonance imaging (MRI). Magnetic field variations of the MRI magnet are applied in at least six different directions generating a three dimensional shape of the diffusion pattern. This technique can be used in neural imaging of white matter due to the orientation of axon bundles and the associated water flow.

(More? Magnetic Resonance Imaging)

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? Genital System Development | Endocrine System Development)

dilate and curettage

(D and C, D&C) A clinical gynecological term referring to the medical procedure involves opening of the cervix (dilate) and scraping away of the uterus lining or endometrium using a tool, the curette (curettage). This material can then be examined.

(More? Menstrual Cycle)

diminished ovarian reserve

Clinical ART term for a diagnosis that means that the ability of the ovary to produce eggs is reduced due to congenital, medical, or surgical causes or advanced age.

(More? In Vitro Fertilization)

dioscorea bulbifera

A plant, the "air potato" which contains the steroid diosgenin used historically for progesterone synthesis.

(More? Menstrual Cycle)

diploid

(Greek, di = double + ploion = vessel) Having two sets of chromosomes, the normal state for all cells other than the gametes.

(More? Fertilization | Week 1)

diplotene phase

(diplotene stage) See entry diplotene stage.

diplotene stage

(diplotene phase, Greek, diplonema = "two threads") A meiotic cell division stage seen during prophase I. Prophase I is further divided into 5 stages based upon changes associated with the synaptonemal complex structure that forms between two pairs of homologous chromosomes. In diplotene, this degrades and the chromosomes separate from one another a small amount giving this appearance. It is possible that some chromosome uncoiling may also occur allowing some gene transcription. In the developing human ovary, oocytes remain at the diplotene stage from fetal life through postnatal childhood, until puberty when the lutenizing hormone (LH) surges stimulate the resumption of meiosis.

Prophase I Stages - Leptotene - Zygotene - Pachytene - Diplotene - Diakinesis

(More? Cell Division - Meiosis | Oocyte Development | Spermatozoa Development | Week 1)

disomy

Genetic term referring to the presence of two chromosomes of a homologous pair in a cell, as in diploid. See chromosomal number genetic disorders uniparental disomy and aneuploidy. Humans have pairs usually formed by one chromosome from each parent.

(More? Abnormal Development - Genetic | Genital System - Abnormalities)

Disorder of Sex Development

(DSD) A new terminology to describe disorders of sex development. The previous human sex development terminology (intersex, true hermaphrodites, male pseudohermaphrodites and female pseudohermaphrodites) are considered outdated and stigmatising and have been replaced with the general term "Disorders of Sex Development" (DSD) established by the Consensus statement on management of intersex disorders. International Consensus Conference on Intersex. Lee PA, Houk CP, Ahmed SF, Hughes IA; International Consensus Conference on Intersex organized by the Lawson Wilkins Pediatric Endocrine Society and the European Society for Paediatric Endocrinology. Pediatrics. 2006 Aug;118(2):e488-500. PMID: 16882788 | Pediatrics Link

(More? Genital System - Abnormalities)

diverticulum

(Latin, diverticulum = by-road) blind tubular process, also used to describe a sac or pouch in organ or seen in the colon. Occurs often in development when a new structure is forming from a epithelia or tract branch or in the initial/early stages of an epitheilal-mesenchymal interaction. The plural term is diverticula. Can also be found in normal and abnormal adult anatomical structures.

(More? Developmental Mechanism - Epithelial Mesenchymal Interaction | GIT Abnormalities - Meckel's Diverticulum)

dizygotic twins

(fraternal twins, non-identical) Twins resulting from two fertilization events, involving two separate oocyte (egg, ova) and spermatozoa (sperm). The other form of twinning, monozygotic twins, results from a single fertilization event.

(More? Abnormal Development - Twinning)

DNA

Acronym for "D"eoxyribo"N"ucleic "A"cid. The genetic material found in mammalian chromosomes and mitochondria. Consisting of 4 nucleic acids (ATCG) that combine in a triptych (3 nucleotide) code for protein amino acids (3 nucleotides = 1 amino acid).

(More? Molecular Development)

DNA duplex

The double stranded base-paired "D"eoxyribo"N"ucleic "A"cid (DNA) forming a helix. This paired strand forms the basic structure of the nucleotide genetic material forming with proteins the chromosomes.

(More? Molecular Development)

Dolly

The name given to the first cloned sheep (1996) generated from an adult mammary gland cell. The name "Dolly" came from Dolly Parton a play on the mammary cell association.

(More? Week 1 - Cloning)

dominant gene

Genetic term describing the gene determining phenotype, allelic pair not determining a phenotype is therefore the recessive gene.

(More? DNA Notes)

dominant inheritance

With autosomal dominant inheritance, there is an error in one of the 22 chromosome pairs. But the damaged gene dominates over the normal gene received from the other parent. If one of the parents has a disease caused by an autosomal dominant gene, all the children will have a 50 per cent risk of inheriting the dominant gene and a 50 per cent chance of not inheriting it. The children who do not inherit the damaged dominant gene will not themselves suffer from the disease, nor will they be able to pass the gene on to future children. This type of inheritance is present for example in Huntington's disease.

(More? DNA Notes)

donor embryo

An embryo formed from the egg of a woman who has donated it for transfer to a woman who is unable to conceive with her own eggs (the recipient). The donor relinquishes all parental rights to any resulting offspring. (More? Week 1 Notes)

doppler velocimetry

A prenatal diagnostic technique using ultrasound which can measure the flow rate of liquids through various vessels including: utero-placental vessels, fetal brain, heart, liver perfusion, and ultrasound evaluation of fetal organs. (Prenatal Diagnosis)

dormant

(French, dormire = to sleep) Referring to a stage in the development of a seed, in which growth is suspended until restarted by environmental cues.

dorsal aorta

Major embryonic blood vessel lying in the splanchnic mesoderm running the length of the embryo, begins as a pair of dorsal aortas (dorsal aortae) which fuse to form a single vessel. Will eventually form the descending thoracic aorta.

(More? 2009 Lecture - Heart | Heart Notes)

dorsal aortae

Term describing the two dorsal aortas.

(More? 2009 Lecture - Heart | Heart Notes)

dorsal root ganglia

(drg, spinal ganglia) The sensory ganglia derived from the neural crest lying laterally paired and dorsally to the spinal cord (in the embryo found ventral to the spinal cord). Connects centrally with the dorsal horn of the spinal cord.

(More? Neural Crest Notes)

Down syndrome

( trisomy 21) Common name for trisomy 21, the most common human aneuploidy where an extra copy of chromosome 21 is found in the cell genome.

(More? trisomy 21)

down syndrome cell adhesion molecule

(DSCAM) Protein member of the immunoglobulin superfamily and a new class of neural cell adhesion molecules. Expressed in the developing nervous system for neuronal cell recognition in the process of self-avoidance. Potentially responsible for the Down syndrome mental retardation and visceral anomalies (Hirschsprung disease, intestinal atresia).

(More? trisomy 21)

dpc

Acrynomn for days post coitum, used often in staging embryonic development in animal models.

DSD

Acronym for Disorders of Sex Development.

(More? Genital System - Abnormalities)

DTPa

Acronym for "D"iptheria-"T"etanus-acellular "P"ertussis vaccine.

(More? Normal Development- Immunization)

duct of Bellini

Historic anatomical term for the papillary collecting duct within the renal medullary region of the kidney.

(More? Renal System Development)

ductal plate

A mesenchymal structure in the developing liver that is remodelled to generate the intrahepatic bile ducts (IHBD). Developmental abnormalities, "ductal plate malformation", arise from failure to reorganise.

(More? Liver Development)

ductuli efferentes

In the 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? Testis Development | Spermatozoa Development | Lecture - Genital Development | Genital System Development)

ductus arteriosus

(Botallo's duct) A prenatal vascular "shunt" which connects the left pulmonary artery and the descending aorta. Postnatal neonatal patency (patent ductus arteriosus, PDA) is a relatively common congenital cardiac anomaly occurring more frequently in premature infants.

(More? Cardiovascular System Development)

ductus deferens

(vas deferens, Latin, deferens = carrying-away vessel)

Spermatozoa Duct Pathway: seminiferous tubule - straight tubule - rete testis - ductuli efferentes - ductus epididymidis - ductus deferens

(More? Testis Development | Spermatozoa Development | Lecture - Genital Development | Genital System Development)

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.

Spermatozoa Duct Pathway: seminiferous tubule - straight tubule - rete testis - ductuli efferentes - ductus epididymidis - ductus deferens

(More? Testis Development | Spermatozoa Development | Lecture - Genital Development | Genital System Development)

ductus venosus

The vitelline blood vessel lying within the liver that connects (shunts) the portal and umbilical veins to the inferior vena cava and also acts to protect the fetus from placental overcirculation. Absence can cause hydrops fetalis and the umbilical vein then drains directly into the inferior vena cava or right atrium. Postnatally this shunt functionally closes then structurally closes and degenerates to form it the ligamentum venosum.

(More? Cardiovascular System Development)

Duffy blood group

Blood typing term referring to Duffy antigens that are located on a glycoprotein on erythrocytes and other cells throughout the body. Discovered in 1950 as a new blood group antibody in the serum of a multi-transfused hemophiliac patient and the reactive red-cell antigen was identified in 65% of random caucasians, and the systemic name Duffy was proposed. This was the first blood group mapped to an autosome (chromosome 1) and the glycoprotein acts as a chemokine receptor (Duffy antigen receptor for chemokines) and also in malarial infection.

(More? Abnormal Development - Malaria | Blood Development | PMID20932074)

duodenum

(Latin, duodenarius = twelve, due to approximate length of 12 finger-widths) First part of small intestine lying between the end of the stomach (pyloric valve) and the jejunum.

(More? Gastrointestinal Tract Development)

dura mater

(Latin, dura mater = hard mother) The outer tough connective tissue meningial coat of the 3 layers that cover the central nervous system of 3 layers (overlays the arachnoid mater middle layer and pia mater inner layer). These three connective tissue layers have different embryonic origins: dura is from mesoderm, pia mater and arachnoid layers are neural crest in origin.Duramater at the level of the spinal cord is separated from the periosteum of the vertebral canal by an epidural space.

(More? Image - Meninges cartoon | Neural System Development | Axial Skeleton)

dynorphin

Protein whos full biological function unknown, 2 possibilities. In development, neuroendocrine regulation of the developing hypothalamo-pituitary-adrenal (HPA) axis. Secondly, a potential endogenous opioid peptide which has a high affinity for the kappa-opioid receptor.

(More? Endocrine Notes)

dysbindin

A protein that functions in some neurons for the biogenesis of lysosome-related organelles (LROs) and dopamine receptor trafficking. This protein has been also implicated in the pathogenesis of the neural disorder, schizophrenia.

(More? PMID: 19887632)

dysfunctional uterine bleeding

(DUB) Clinical term used to describe menstrual cycle abnormal uterine bleeding in the absence of an organic disease.

(More? Menstrual Cycle)

dysmenorrhoea

A menstrual period pain which can be primary (increased sensitivity to the prostaglandins) or secondary (pathological), can be common with no associated abnormality or in association with ovarian cysts or endometriosis.

(More? Menstrual Cycle)

dysraphism

(Greek, rhaphe = suture) The clinical term often used to describe the defective fusion of the neural folds. The position and degree of failure of fusion will result in either embryonic death or a range of different neural defects. The way (mode) in which the human neural tube fuses has been a source of contention. In humans, fusion appears to initiate at multiple sites but the mode is different from that found in many animal species used in developmental studies. The defect severity dependent upon level within the tube and degree of failure (caudal failure - spina bifida, cranial failure - anancephaly)

(More? Neural System - Abnormalities | Lecture - Ectoderm 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 4) Embryology D. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/D

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