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Glossary Links

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N

nanog

Homeodomain-containing transcription factor involved in maintaining embryonic stem (ES) cell self-renewal. Name is derived from Celtic "Tir Na Nog" a mythologic Celtic land of the ever young. Also expressed in implanting embryos and for the early proliferation and survival of primordial germ cells (PGCs).
(More? Stem Cells | OMIM - NANOG | PMID 19906868 | PMID 20539761)

nanoparticles

Nanomaterials are a new technology used commercially in many different areas (cosmetics, therapeutic agents and household products), generally with no biological safety regulations yet in place for their use. Silver nanoparticles (Ag-np) are used for their antimicrobial potential and have been shown in some studies to have an anti-proliferative activity.
(More? PMID 19761582)

nail-patella syndrome

(NPS) rare (1/50,000) Autosomal dominant disorder characterized by hypoplastic or absent patellae, dystrophic nails, dysplasia of the elbows and iliac horns. Potentially due to mutations in LMX1B, a LIM-homeodomain transcription protein.
(More? Nail Development | Image - NPS nails | OMIM - nail-patella syndrome | OMIM - LMX1B)

NAS

Acronym for Neonatal Abstinence Syndrome describes neonatal affects of discontinuation of opioids exposure and dependence during fetal development in the uterus.

nasal placode

(olfactory placode) (placode - Greek, plax = "plate" or "scale", eidos = shape or form) Cranial region of thickened ectoderm that will generate the sensory olfactory epithelium of the nose required for smell.
(More? Sensory - Smell Development)
nasolacrimal groove
nasolacrimal groove

nasolacrimal groove

(lacrimal groove, Latin, nasus = "nose", lacrima = "tear") During embryonic early face development, an obvious depression is seen extending from the developing eye to the olfactory sac and separates the lateral nasal process from the maxillary process.
(More? Sensory - Vision Development | Head Development)

natural family planning

(NFP) Refers to a range of techniques, with variable accuracy, used by women to monitor their fertility when trying to either avoid pregnancy or trying to conceive.
(More? Menstrual Cycle | Fertilization | Billings Ovulation Method)

natural killer cell

(NK) A lymphoid innate immune cell of the cytotoxic type 1, that in the adult have roles in anti-infection and anti-cancer. NK cells form at least two classes based on surface marker expression (CD56dim and CD56bright) and anatomical location (peripheral blood and secondary lymphoid tissue/non-lymphoid organs). Uterine NK cells (uNK) are thought to have a role in implantation.
(More? Immune System Development | Implantation)

necrosis

(Greek, nekros = corpse) Pathological cell death from extrinsic injury in contrast to apoptosis or programmed cell death. Cell lyses releasing cytoplasmic contents which may also have a role in initiating an inflammatory response.

necrotizing enterocolitis

(Greek, nekros = corpse) Gastrointestinal tract pathology occurring postnatally in mainly in premature and low birth weight infants (1 in 2,000 - 4,000 births). The underdeveloped gastointestinal tract appears to be susceptible to bacteria, normally found within the tract, to spread widely to other regions where they damage the tract wall and may enter the bloodstream. The condition only occurs after postnatal bacterial colonization and not in the sterile intrauterine microenvironment prior to birth. Pathological cell death from extrinsic injury, cell lyses releasing cytoplasmic contents which may also have a role in initiating an inflammatory response.
(More? Gastrointestinal Tract Abnormalities | Neonatal Development | Medline Plus - Necrotizing Enterocolitis)

Neisseria gonorrhoeae

A gram-negative bacteria that is the cause of the disease Gonorrhea, a sexually transmitted disease (STD). About half of the women with gonorrhea are also infected with chlamydia, another common STD that can result in sterility.
(More? Abnormal Development - Bacterial Infection | Pubmed Health)

nebenkern

(German, nebenkern = subsidiary nucleus) A mitochondrial aggregate formed during developemnt of the Drosophila spermatazoa. The individual mitochondria fuse into two giant mitochondria arranged in a sphere of many layers of "onion-like" wrapped mitochondrial membranes. This process appears to only occur in some insect spermatogenesis.
(More? Fly Development | Meiosis | Spermatozoa Development)

nematode

(roundworm) A phylum of small worms, with the species Caenorhabditis elegans (C.Elegans) used in developmental, genetic and neural studies.
(More? Worm Development)

neonatal

Term used in relation to the newborn infant and up to four weeks old.


neonatal abstinence syndrome

(NAS) Syndrome describes neonatal affects of abrupt discontinuation of opioids exposure and fetal dependence during development in the uterus. Opioid exposure can occur through prescription or illegal drug use. A recent USA clinical study (PMID 22546608) has identified a trend increase in NAS live birth incidence (2000, 1.2/1,000; 2009 3.39/1000). Animal models have identified neural development abnormalities associated with prenatal opioid exposure.
(More? Abnormal Development - Drugs | Illegal Drugs | Neural System - Abnormalities)

neonatal diabetes

Diabetes mellitus that has been diagnosed within the first 6 months of life. There are two main clinical subtypes: persistent, permanent neonatal diabetes (PNDM) and remitting and frequently relapsing, transient neonatal diabetes (TNDM). Permanent neonatal diabetes has been shown to result from mutations in the preproinsulin (INS) gene.
(More? Endocrine - Pancreas Development | Abnormal Development - Maternal Diabetes)

neonatal bacterial sepsis

(neonatal sepsis) A newborn infection by microorganisms, located mainly in the maternal genital tract, either by transplacental infection or an ascending infection or at delivery. Treated with an antibacterial drug (penicillin, ampicillin, gentamicin, cefotoxine, etc.) and given systemically (intravenous or intramuscular). Note that antibiotics are also given to infants for reasons other than neonatal sepsis.

neonatal intensive care unit

(NICU) A hospital facility or unit staffed and equipped to provide continuous mechanical ventilatory support at any time during the infant’s hospital stay following delivery.

neonatal sepsis

(neonatal bacterial sepsis) A newborn infection by microorganisms, located mainly in the maternal genital tract, either by transplacental infection or an ascending infection or at delivery. Treated with an antibacterial drug (penicillin, ampicillin, gentamicin, cefotoxine, etc.) and given systemically (intravenous or intramuscular). Note that antibiotics are also given to infants for reasons other than neonatal sepsis.

neonatal transient hypothyroxinaemia

A clinical condition that occurs postnatally with a temporary reduction in concentrations of Total T4 or Free T4, with normal or low concentrations of thyroid stimulating hormone (TSH).
(More? Thyroid Development | PMID 20930033)

neoteny

(juvenilization) Term used to describe the adult retention of traits that occur normally at an earlier stage of development (fetal, juvenile or larval). This has also been described as a developmental slowing or delay.

neoplastic rest

In kidney development, a neoplastic rest can develop under either genetic or epigenetic influence from a hyperplastic rest, originating from an embryonic blastema cell. Normally the majority of nephrogenic rests either regress or become dormant.
(More? Wilm's tumour | Renal System - Abnormalities)

nephrin

Structural protein of the kidney nephron, forming a major component of the glomerular slit diaphragm. Also acts late in the process of podocyte differentiation as a signaling molecule influencing foot process formation and the maintenance of podocyte integrity.
(More? Renal System Development | Lecture - Renal Development)

nephroblastoma

A childhood kidney cancer see Wilm's tumour
(More? Renal System Development | Lecture - Renal Development)

nephrocan

A secreted small leucine-rich repeat proteoglycan/protein expressed during development in the kidney and pylorus of the gastrointestinal tract and may act through inhibition of TGF-beta signaling.
(More? :(More? Renal System Development | Lecture - Renal Development | PMID 16990280 | PMID 19877272)

nephrogenic rest

A kidney term used to describe the embryonic blastema cells which persist and under either genetic or epigenetic can change to become a neoplastic rest. These neoplastic rests can develop postnatally as a benign form (adenomatous rest) or a malignant Wilm's tumour form. The rests are further characterised by the time of generation leading to different anatomical kidney locations: early intralobar nephrogenic rests (within the renal lobe) and late pelilobar nephrogenic rests (periphery of the renal lobe).
(More? Wilm's tumour | Renal System Development | Renal System - Abnormalities | Lecture - Renal Development)

nephron

(Greek, nephros = kidney) The micro-anatomical structure that forms the functional unit of the kidney.
(More? Renal System Development | Lecture - Renal Development)

nephros

(Greek, nephros = kidney) Term used to describe features associated with the kidney and therefore used in other kidney development (pronephros, mesonephros, metanephros) and structures (nephron, nephric, nephroblastoma).
(More? Renal System Development | Lecture - Renal Development)

nesfatin-1

A protein described as "satiety molecule", a anorectic peptide cleaved from the N-terminal of the precursor protein nucleobindin 2 (NUCB2). Identified centrally in hypothalamus and nucleus of solitary tract (NTS) regions that regulate feeding and metabolism and peripherally in the endocrine cells of the stomach, pituitary and pancreas.
(More? Hypothalamus | PMID 17627999)

nestorone

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) Trimegestone and Nestorone are currently the most potent fourth-generation progestins with no androgenic or estrogenic actions.
(More? Menstrual Cycle)

netrin

A protein that has roles in both cell migration and in neural development axon guidance (secreted and GPI-anchored proteins). Secreted netrins can act either positively (attractive) or negatively (repulsive). The name “netrin” is derived from the Sanskrit word "netr" meaning “one who guides”.
(More? Neural System Development | Molecular Development)

neuralation

The general term used to describe the early formation of the nervous system. It is often used to describe the early events of differentiation of the central ectoderm region to form the neural plate, then neural groove, then neural tube. The nervous system includes the central nervous system (brain and spinal cord) from the neural tube and the peripheral nervous system (peripheral sensory and sympathetic ganglia) from neural crest. In humans, early neuralation begins in week 3 and continues through week 4.
(More? Neural System Development | Neural Crest Development | Week 3 | Lecture - Ectoderm Development | Lecture - Neural Crest Development)

neural crest

A cell region at edge of neural plate, then atop the neural folds, that remains outside and initially dorsal to the neural tube when it forms. These paired dorsal lateral streaks of cells migrate throughout the embryo and can differentiate into many different cell types (= pluripotential). Those that remain on the dorsal neural tube form the sensory spinal ganglia (DRG), those that migrate ventrally form the sympatheitic ganglia. Neural crest cells also migrate into the somites and regions throught the entire embryo.
(More? Neural Crest Development | Lecture - Neural Crest Development)

neural folds

The central region of the trilaminar embryo ectoderm called the neural plate region folds dorsally, generating two neural folds, which later fuse to form the neural tube. The mid-line depression between the two folds is described as the neural groove. In humans at approximately day 18-19 post-fertilization to form the neural groove, which then fuses to form an initially open at either end hollow neural tube. The neural tube forms the central nervous system (brain and spinal cord).
Developmental sequence: neural plate -> (day 18-19) neural groove -> neural tube -> Central Nervous System (brain and spinal cord)
(More? Neural System Development | Lecture - Ectoderm Development)

neural groove

The second stage in early development of the central nervous system. In the trilaminar embryo (ectoderm, mesoderm, endoderm) the central region of the ectoderm (in the midline above the mesodermal notochord) initially forms a columnar epithelium described as the neural plate. This epithelium will fold dorsally, beginning in humans at approximately day 18-19 post-fertilization to form the neural groove, which then fuses to form an initially open at either end hollow neural tube. The neural tube forms the central nervous system (brain and spinal cord).
Developmental sequence: neural plate -> (day 18-19) neural groove -> neural tube -> Central Nervous System (brain and spinal cord)
(More? Neural System Development | Lecture - Ectoderm Development)

neural plate

The first stage in early development of the central nervous system. In the trilaminar embryo (ectoderm, mesoderm, endoderm) the central region of the ectoderm (in the midline above the mesodermal notochord) initially forms a columnar epithelium described as the neural plate. This epithelium will fold dorsally to form the neural groove, which then fuses to form an initially open at either end hollow neural tube. The neural tube forms the central nervous system (brain and spinal cord).
Developmental sequence: neural plate -> (day 18-19) neural groove -> neural tube -> Central Nervous System (brain and spinal cord)
(More? Neural System Development | Lecture - Ectoderm Development)

neural stem cell

(NSC) A stem cell within the central nervous system (CNS) that can proliferate indefinitely and give rise to either neurons, astrocytes, and oligodendrocytes.
(More? Stem Cells | Neural System Development)

neural stem cell niche

Locations within the nervous system that multipotent stem cells reside and participate in specialized microenvironments that support cell self-renewal and differentiation.
(More? Stem Cells | Neural System Development)

neural tube

The third stage in early development of the central nervous system. In the trilaminar embryo (ectoderm, mesoderm, endoderm) the central region of the ectoderm (in the midline above the mesodermal notochord) initially forms a columnar epithelium described as the neural plate . This epithelium will fold dorsally to form the neural groove, which then fuses to form initially a hollow tube open at either end (neuropores). The neural tube forms the central nervous system (brain and spinal cord).
Developmental sequence: neural plate -> (day 18-19) neural groove -> neural tube -> Central Nervous System (brain and spinal cord)
(More? Neural System Development | Lecture - Ectoderm Development)

neuroblastoma

A tumour derived from neural crest cells.
(More? Neural Crest System - Abnormalities)

neurocysticercosis

(NCC) Clinical term for a zoonotic parasitic disease caused by infection with the larval stage of Taenia solium (pork tapeworm) infestation of the central nervous system. The ventricle infestation is due to active passage of hexacanthous embryo through the cappilaries of the choroid plexus.
(More? Abnormal Development - Environmental | Ventricular System Development)

neuroenteric canal

The canal or opening existing early in trilaminar embryo development that provides transient communication between the amnion and the yolk sac. Canal forms as part of axial process development, the precursor to the notochord.
(More? Neural System Development)

neuroepithelial progenitor cell

(NEP, neural stem cells, glial stem cells) The central nervous system neural stem cell that forms all neurons and glial cells. These cells are derived from the epithelia of the ectoderm forming the neural plate then the neural tube and then undergoing cell migration, proliferation, and differentiation.
(More? Neural System Development)

neurogenesis

The process of formation of the neural system. Early neurogenesis begins with segregation of the neural plate from the ectoderm of the trilaminar embryo by folding to form initially the neural groove, which then fuses to form the neural tube (the central nervous system progenitor, brain and spinal cord) and associated neural crest. Later neurogenesis in the central nervous system is the proliferation of ventricular neural stem cells (neuroepithelial progenitor cells), differentiation, migration and lamination of the developing neural system.
Early developmental sequence: neural plate -> (day 18-19) neural groove -> neural tube -> Central Nervous System (brain and spinal cord).
(More? Neural System Development)

neurogenin-3

(NEUROG3) Gene expressed in endocrine progenitor cells (including pancrea islet cells) and required for endocrine cell development in pancreas and intestine. Mutation in this gene depletes intestinal enteroendocrine cells resulting in malabsorptive diarrhea.
(More? Endocrine System Development | Endocrine - Pancreas Development)

neuron

(neurone) The cell forming the unit basis of the nervous system (both central and peripheral) capable of generating an action potential and releasing neurotransmitter. There are many different types of neuronal cells.
(More? Neural System Development | Lecture - Ectoderm Development)

neuron-derived neurotrophic factor

A recently identified neural growth factor expressed by a range of mouse neurons (Cajal-Retzius cells, cortex neurons, hippocampus neurons, olfactory mitral cells, cerebellar purkinje cells, cerebellar granular cells and spinal neurons). The growth factor supports hippocampal neuron neurite outgrowth and protects against excitotoxicity and amyloid beta-peptide toxicity. A secretory protein glycosylated and disulfide-bonded that contains a fibronectin type III domain.
(More? Neural System Development | Lecture - Ectoderm Development | PMID 20969804)

neuropilin

(NRP1, NRP2) A transmembrane receptor acting as a coreceptor to a tyrosine kinase receptor for both vascular endothelial growth factor (VEGF) and semaphorin.
(More? OMIM)

neuropore

The initial two openings at either end of hollow neural tube called the cranial (rostral, anterior) and caudal (posterior). In humans, the cranial (rostral, anterior) neuropore closes (day 25) about 2 days before caudal (posterior) that closes at somite level 32 to 34. The developmental abnormality classed as Neural Tube Defects (NTDs) can be due to failure of these two neuropores to developmentally close and has been associated with low dietary folic acid.
(More? Neural System Development | Lecture - Ectoderm Development | Neural Abnormalities | Folic Acid and Neural Tube Defects)

neutrophil

(neutrophil granulocytes) A white blood cell granulocyte that has a central role in the inflammatory process, invade sites of infection in response to growth factors. Cell nucleus has a characteristic lobed appearance (3-5 lobes), the number of lobes increases with cell age. During the menstrual cycle, a cyclic change in neutrophil cell number in the endometrium is shown by vaginal smear.
(More? Cardiovascular System - Blood Development| Human Vaginal Smear Cells)

neurotrophin

Secreted protein family that interacts with membrane tyrosine kinase receptors. Named originally on their role in neuron growth (survival, axon growth) now identified as having many other roles in development.
(More? Neural System Development | Molecular Development)

NICM

Acronym for Neonatal and Infant Close Monitoring. A clinical term used in the UK for: i) infant births before 32 weeks gestation, ii) unwell neonates born after 32 weeks and iii) for term infants with significant growth and weight faltering. Previously also referred to as the Low Birthweight.
(More? Postnatal - Growth Charts | Birth - Preterm)

nicotine

A natural alkaloid ingredient in tobacco leaves, where it provides protection by acting as a botanical insecticide. There is an association between physical defects among newborns and maternal smoking tobacco during pregnancy.
(More? Abnormal Development - Smoking)

nicotinamide

The amide of vitamin B3 and is the precursor for the coenzyme beta-nicotinamide adenine dinucleotide (NAD+) and has been used in humans for the treatment of diabetes and bullous pemphigoid. Identified in mice as a potential protective agent against ethanol-induced cell death in the developing brain by inhibiting ethanol-induced caspase-3 activation.
(More? Neural System Development | Abnormal Development - Fetal Alcohol Syndrome | PMID 16478293 | PLoS - Medicine Article)

nidation

Term used to clinically describe implantation within the uterus.
(More? Implantation | Week 2)

NIPT

Clinical acronym for Non-Invasive Prenatal Testing. This is a new analytical technique that analyzes cell-free fetal DNA circulating in maternal blood. Testing of circulating cell-free fetal DNA (ccffDNA) can be carried out after 10 weeks (between 10-22 weeks) analysis can take a week or more.
(More? Non-Invasive Prenatal Testing | Prenatal Diagnosis)

Nitabuch's layer

(fibrinoid layer) The layer formed at maternal/fetal interface during placentation and is thought to act to prevent excessively deep conceptus implantation. Fibrin-type fibrinoid (maternal blood-clot product) and matrix-type fibrinoid (secreted by invasive extravillous trophoblast cells).
(More? Placenta Development)

nitrofen

A diphenyl ether herbicide teratogen used in rodent development to generate a range of developmental abnormalities, including congenital diaphragmatic hernia.
(More? Diaphragm | Respiratory Abnormalities | Chemicals | Report on Carcinogens)

Nogo

(Reticulon 4, RTN4, Neurite Growth Inhibitor 220) One of several myelin-associated proteins with inhibitory effects for neuronal neurite outgrowth. Nogo exists as 3 splice transcript variants (NOGO-A, NOGO-B and NOGO-C) which are differentially expressed in the developing central nervous system. Also associated with autoimmune demyelination, shown in models of multiple sclerosis (MS) such as experimental autoimmune encephalomyelitis (EAE).
(More? Nogo-A | Neural System Development | OMIM - Reticulon 4)

Nogo-A

A myelin-associated protein which can inhibit neurite outgrowth and prevent regeneration in the adult central nervous system. Secreted by oligodendrocytes in the central nervous system, but not by Schwann cells in the peripheral nervous system.
(More? Neural System Development | OMIM - Reticulon 4)

nondisjunction

(non-disjunction) Genetics term describing the failure of any paired chromosomes to separate (disjoin) during cell division. This leads to an uneven distribution of chromosomes to daughter cells, both chromosomes go to one daughter cell and none to the other. In humans, the most common form of nondisjunction occurs in autosomal chromosome trisomies, trisomy 21 (Down's syndrome) and trisomy 18.
(More? Trisomy 21 | Trisomy 18 | Trisomy X | Abnormal Development - Genetic)

nonnutritive suck

(NNS) Term used to describe a coordinated motor behaviour that has been used as an indicator of brain development and pre-feeding skill in preterm and term infants. One of the earliest-appearing somatic motor rhythm appears initially between 15 to 18 weeks gestational age (GA).
(More? PMID 22888359)

nonvertex presentation

Birth term referring to the presentation (fetal presentation) of a part of the infant’s body other than the upper and back part of the infant’s head to the birth canal.
(More? Birth)

nosocomial

An infection acquired with medical treatment, generally associated with hospitals. Some forms of acquired infections may impact on fetal development either directly, by transmission to the fetus, or indirectly through maternal effects such as fever.
(More? Abnormal Development)
notch
notch

notch

A cell surface single-pass transmembrane receptor family (1-4) required for asymmetric cell division. Acts as a receptor for Jagged (1,2) and Delta-like (1,3,4) proteins and also interacts with a negative regulator (Numb) which is down-regulated by notch. Asymmetry of cell division allows generation of distinct progeny from a single cell division required in many developmental processes including neurogenesis.
(More? OMIM - NOTCH | OMIM - NUMB | PMID 19799767)

notch-regulated ankyrin-repeat protein

(Nrarp) A protein downstream target of the Notch signaling pathway. Nrarp is a 114 amino acid protein with a carboxy-terminal domain containing two ankyrin-repeat motifs. This protein has been identified as a component of somitogenesis, expressed in presomitic mesoderm, and T cell development, from hematopoietic stem cells.
notochord Human (stage 8)
notochord human (stage 8)

notochord

(axial mesoderm, chorda dorsalis) The rod of cells lying in the midline of the trilaminar embryo mesoderm layer ventral to the neural tube. Thought to have at least 2 early roles in development and later roles in patterning surrounding tissues. 1. Mechanical, influencing the folding of the early embryo; 2. Morphogenic, secreting sonic hedgehog a protein which regulates the development of surrounding tissues (neural plate, somites, endoderm and other organs). In humans, the notochord forms in week 3 and is eventually lost during the formation of the vertebral column. The notochord persists in amphioxus and in part in fish and amphibia,
(More? Notochord | Development Animation - Notochord | Musculoskeletal | Neural | Sonic hedgehog)

Non-Hodgkin's lymphoma

(NHL) A type of cancer where the cause is unknowm and may develop in people with suppressed immune system. Treatment may cause premature ovarian failure. A recent study has shown CHOP therapy (cyclophosphamide 750 mg/m2, doxorubicin 50 mg/m2, vincristine 1.4 mg/m2 (maximum 2 mg) and prednisone 100 mg/day for 5 days) does not affect the ovarian function or fertility.
(More? Medline Encyclopedia | PMID 15817583)

Nrarp

Acronym for notch-regulated ankyrin-repeat protein, which is a downstream target of the Notch signaling pathway. Nrarp is a 114 amino acid protein with a carboxy-terminal domain containing two ankyrin-repeat motifs. This protein has been identified as a component of somitogenesis, expressed in presomitic mesoderm, and T cell development, from hematopoietic stem cells.

NRT

An acronym for Nicotine Replacement Therapy, a method of replacing cigarette nicotine by either nicotine transdermal patches, nicotine gum, nicotine lozenges or nicotine inhalers.
(More? Abnormal Development - Smoking | Smoking Workshop)

nuage

(French, Nuage = "cloud") An electron microscope visible feature found in germ line cells, originally in drosophila but also in mouse. Appear as electron-dense granules with a perinuclear location.
(More? Image - mouse oocyte)
nuchal translucency
nuchal translucency

nuchal translucency

(NC, fetal nuchal-translucency thickness) A diagnostic measurement in the fetal neck region (nuchal) by ultrasound (translucency) for Trisomy 21 and other genetic disorders. Carried out usually in first trimester gestational age (GA) 10 – 14 weeks. A trans-abdominal ultrasound showing a fetal sagittal section scan at a magnification that the fetus occupied at least 75% of the image. Measured is the maximum thickness (mm) of the subcutaneous translucency between the skin and the soft tissue overlying the cervical spine. At this stage, nuchal translucency thickness normally increases with fetal crown-rump length, and the measurement of crown-rump length also should be taken into account.
(More? Trisomy 21 | Ultrasound | PMID 9717920)

nucleolus

Cell nucleus region that is the ribosome factory of the cell where ribosomal genes (rDNAs) are transcribed, the 47S precursor ribosomal RNAs (pre-rRNAs) are cleaved, processed and assembled with the 80 ribosomal proteins and the 5S RNA to form the 40S and 60S ribosomal subunits. The mammalian nucleolus has 3 components; 1. fibrillar centres are clear areas, 2. dense fibrillar component, 3. granular component (granules of 15–20 nm in diameter).

nucleolus precursor bodies

(NPBs, nucleolus-like bodies in oocytes) Cell region of nucleus embryonic nuclear organelles found in oocytes and early embryo of maternal origin, that are replaced by the typical fibrillo-granular nucleoli.
(More? Oocyte | PMID 25495074)

nucleus pulposus

Anatomical core within the intervertebral disc of the vertebral column. Apparently the only adult structure formed from the embryonic notochord. The nucleus pulposus is a gel-like structure surrounded by a thick fibrous tissue and fibrocartilage forming the annulus fibrosus, formed embryonically from the sclerotome.
(More? Notochord | Axial Skeleton Development)

numb

A membrane-associated protein (also Numblike) involved in asymmetric cell division along with notch. Acts as a negative regulator of notch which can also down-regulate numb expression. Asymmetry of cell division allows generation of distinct progeny from a single cell division required in many developmental processes including neurogenesis.
(More? Molecular Development | JCB - Notch and Numb | OMIM - NUMB | | OMIM - NUMBL | OMIM - NOTCH)


NVSS

Acronym for National Vital Statistics System used to monitor United States data on births, deaths, marriages, divorces, and fetal deaths. The National Center for Health Statistics (NCHS), is the Federal agency responsible for use of the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) in the United States. The ICD-10 is copyrighted by the World Health Organization (WHO), which owns and publishes the classification. The equivalent Australian monitoring system is called {A#ACAMS|ACAMS]]); the European monitoring system is called (eurocat|).
(More? USA Statistics | NVSS | NVSS - Births | NVSS- Fetal Deaths)


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.


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Cite this page: Hill, M.A. 2017 Embryology N. Retrieved June 26, 2017, from https://embryology.med.unsw.edu.au/embryology/index.php/N

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