p
a prefix combined with a number to indicate a protein of a specific molecular size (mass). Often given initially if no specific "name" has been given to the protein, see examples in the following entries.
a cell cycle protein in mammals that suppresses G1-Cdk activity in G1 and is frequently inactivated in cancer. Belongs to a class of Cdk inhibitory proteins. Nomenclature is p for protein and 16 is molecular size (16,000 daltons).
(More? Week 1 Mitosis | OMIM Entry for p16)
(recently renamed tp53) a cell cycle related transcription factor that promotes transcription of genes that induce cell cycle arrest or apoptosis in response to DNA damage or other cell stresses. This tumor suppressor gene is mutated in about half of all human cancers. Nomenclature is t for tumor, p for protein and 53 is molecular size (53,000 daltons).
(More? Week 1 Mitosis | OMIM Entry for p53)
a p53 related transcription factor and is essential for the development of stratified epithelia. p63 acts as a "master regulator" controlling stratified epithelial development program, through induction of downstream signals important for epithelial function. Nomenclature is p for protein and 63 is molecular size (63,000 daltons). Reference: R.A. Ihrie etal., Perp Is a p63-Regulated Gene Essential for Epithelial Integrity See also : OMIM Entry for p63
pancreatitis-associated protein -III
(PAP-III) a macrophage chemoattractant, implicated in nerve regeneration as it has been shown to be induced and released from injured nerves. Journal of Neuroscience Paper
a differentiated cell type cell within the gastrointestinal system epithelium. Paneth cells are located at the bottom of crypts of Lieberkühn in the small intestine. Their role is to control of infections by release of several antibacterial substances, including lysozyme. Paneth cell differentiation and positioning is apparently controlled by the developmental signaling protein Wnt.
(More? Gastrointestinal Tract Notes | Molecular Notes | Wnt7a)
Panton-Valentine leucocidin toxin
(PVL) produced by about 2% of Staphylococcus aureus (S aureus) bacteria, occurs very rarely and can be fatal in neonates.
acronym for pregnancy-associated plasma protein-A. Protein produced by both embryo and placenta during pregnancy. Maternal serum concentrations are related to subsequent fetal growth and it is thought to have several different functions, including preventing recognition of the fetus by the maternal immune system.
paramesonephric duct
( = Mullerian duct) paired ducts that form the epithelial lining of female reproductive organs: utererine tube, uterus, upper vaginal canal.
(More? Urogenital Notes)
parietal pleura
outer lining of pleural cavity derived from epithelia of pericardioperitoneal canals from intraembryonic coelom.
(Greek, parthenos = virgin, genesis = birth) development of an unfertilized egg. Occurs mainly in plants but can also occur in animals.
(More? Week 1 Abnormalities | Molecular Development - Epigenetics - Parthenogenesis)
(Latin, parvo = poor) a family of viruses that infect many species. Human parvovirus B19 (a single-strand 5,594 nucleotide DNA Class II virus) infection is also called "fifth disease" and occurs mainly in children. Animal parvoviruses do not infect humans.
(More? Defect - Parvovirus)
name derived from Drosophila gene "paired" (prd) with a box domain. Transcription factor of the helix-turn-helix structural family, DNA binding, and activating gene expression. In human, nine member proteins from Pax-1 to Pax-9.
(More? Molecular Factors - Pax | Molecular Notes)
polychlorinated biphenyls, a class of chemicals linked to developmental defects.
(More? Defects - Chemical Notes)
2,2',4,4',5,50-hexachlorobiphenyl, a form of polychlorinated biphenyls, a class of chemicals linked to developmental defects.
(More? Defects - Chemical Notes)
Peabody Developmental Motor Scale II
(PDMS-2) an early postnatal neurological assessment scale used in screening and diagnosis of neural development.
(More? Neural Notes | Postnatal Development)
undifferentiated mesenchymal cells which surround the growth plate cartilage and regulate chondrocyte differentiation. Involved with endochondral bone formation process.
(More? Bone Notes)
the early postnatal period relating to the birth, statistically it includes the period up to 7 days after birth.
(More? Normal Development - Birth)
statisically refers to the sum of late fetal deaths plus infant deaths within 7 days of birth divided by the number of live births, per 1,000 live births.
(More? Normal Development - Birth | Statistics | Australian Statistics)
located in the sperm head perinuclear region, containing a cytoskeletal element to maintain the shape of the sperm head and functional molecules leading to oocyte activation during fertilization.
(More? Spermatogenesis | Fertilization)
fibrous membrane covering bone except on the surface of joints which are covered in articular cartilage.
(More? Musculoskeletal Notes | Bone Notes)
smooth muscle-like cell which covers over blood vessel endothelial cells.
(More? Cardiovascular Notes | Lymphatic Notes)
peritubular cells
(peritubular myoid cells) stromal cells (mesenchymal) located in the male gonad (testis) seminiferous tubule lying outside the basal membrane in the lamina propria surrounding seminiferous tubulus that regulate Sertoli cell function and contractility of seminiferous tubules. Also used to describe cells found in the kidney glomerulus.
(More? Week 1 - Spermatogenesis)
perivitelline space
(PVS) space between the oocyte (egg) and the surrounding zona pellucida, enlarged in the region where the polar body lies. In mice this has been shown to influence the site sperm entry independent of any asymmetry of the oocyte membrane.
(More? Week 1 - Fertilization | Motosugi N, Dietrich JE, Polanski Z, Solter D, Hiiragi T. Space asymmetry directs preferential sperm entry in the absence of polarity in the mouse oocyte. PLoS Biol. 2006 May;4(5):e135. )
(heparan sulfate proteoglycan 2) an extracellular matrix proteoglycan expressed in the basal lamina of the neuroepithelium.
(More? Neural Notes)
Persistent Pulmonary Hypertension of the Newborn
(PPHN) serious newborn condition due to due to the failure of closure one of the prenatal circulatory shunts, the ductus arteriosus.
(More? Respiratory Development - Birth)
Gut-Associated Lymphoid Tissue (GALT) located in the ileum and appendix (lying between the lamina propria to the submucosa). These immune system structures are the first line of protection against ingested infectious agents.
(More? Gastrointestinal Tract Notes)
PGC
acronym for Primordial Germ Cell, the embryonic cell that will form eventually either egg or sperm cell.
(More? Genital Notes | primordial germ cell movies)
Pre-implantation Genetic Diagnosis, a screening procedure for embryos produced through in vitro fertilisation (IVF) for genetic diseases that would generate developmental abnormalities or serious postnatal diseases.
(More? Week 1 Notes | In Vitro Fertilization Notes)
pharyngeal arches
(= branchial arches, Greek = gill) series of anterior tissue bands that give rise to the structures of the head and neck. In humans, five arches form (1,2,3,4 and 6) but only four are externally visible on the embryo. Each arch has initially identical structures: an internal endodermal pouch, a mesenchymal (mesoderm and neural crest) core, a membrane (endoderm and ectoderm) and external cleft (ectoderm). Each arch mesenchymal core also contains similar components: blood vessel, nerve, muscular, cartilage. Arches differentiate to form different head and structures.
(More? Head Notes | Neural Crest Notes | Endocrine Notes)
phenylketonuria
(PKU) a disease resulting from an inability to break down phenylalanine, an amino acid. Causes mental and motor retardation, microcephaly, poor growth rate and seizures. Can be tested in newborn screening.
(More? Neonatal Screening)
phocomelia
(Greek, phoco = seal, melia = limb) a flipper-like appendage attached to the trunk, as described in the original classical classification of limb deficiencies. Seen in genetic and environmentally derived abnormalities, for example in association with thalidomide.
endocrine gland named as shape resembles a pine cone. Formed from a dorsal outpocket of diencephalon. The hormone melatonin (high in dark, low in day) involved with the diurnal cycle, inhibits pituitary-gonad axis.
(More? Endocrine Notes | Pineal Gland)
Pink Disease
chronic mercury poisoning in infants and young, also called acrodynia (Greek, acrodynia = painful extremities)
(More? acrodynia | Heavy metals | Michigan Health MercurySpillFactsheet_85689_7.pdf)
uppermost end of gastrointestinal and respiratory tract, in the embryo beginning at the buccopharyngeal membrane and forms a major arched cavity within the phrayngeal arches.
(More? Head Notes | GIT Notes | Carnegie stage 13 pharynx)
malarial infection of the placenta by sequestration of the infected red blood cells. Common in regions where malaria is endemic with women carrying their first pregnancy (primigravida).
(More? Abnormal Development | Brown University Maternal Malaria)
Placentophagia
is the maternal ingestion of afterbirth materials (placental membranes and amniotic fluid) that occurs usually during mammalian parturition.
(Greek, plax = plate, eidos = shape or form) A surface ectoderm thickening seen in the early embryo head region. Each pair of placodes will contribute a different component of each sensory system (otic placode, optic placode, nasal placode).
(More? Head Notes)
one of several skull deformities (scaphocephaly, oxycephaly, plagiocephaly, trigoncephaly) caused by premature fusion (synostosis) of different developing skull sutures. Plagiocephaly results from asymmetric coronal suture synostosis.
(More? Skull Notes | Head Notes)
is the thin skin membrane (extending from the fifth digit and the posterior aspect of the forelimb, along the side of the body, to the anterior aspect of the hindlimb) forming the bat wing.
(More? Other Embryos - Bat)
Plan B
a two pill high dose regimen of the oral contraceptive levonorgestrel, 90% effective in preventing pregnancy when taken within 72 hours of unprotected sex. Approved for use in some countries, but not the USA as it is considered an abortifacient not a contraceptive. September 2006, the US Food and Drug Administration has approved the emergency contraceptive Plan B for sale over the counter to women aged 18 or over.
virtual space surrounding lungs, one of the 3 intraembryonic coeloms (pericardial, pleural, peroitoneal). Embryonic origin: walls derived from pericardioperitoneal canals, intraembryonic coelom , coelomic spaces , lateral mesoderm, mesoderm.
(More? Respiratory Notes)
pleuropericardial fold
restricts the communication between pleural cavity and pericardiac cavity, contains cardinal vein and phrenic nerve.
(More? Coelom Notes | Respiratory Notes)
pleuroperitoneal membrane
forms inferiorly at the transverse septum to separate peritoneal cavity from pleural cavity.
(More? Coelom Notes)
(Latin, plexus = a network) used anatomically to describe a network of interconnecting structures either nerves, blood vessels, or lymphatic vessels.
pluripotent
describes the ability of a cell to form any tissue in an embryo.
(More? Stem Cell Notes)
acronym for Pre-Menstrual Syndrome
a small cytoplasmic exclusion body formed from the excess DNA formed during the egg meiotic cycle and following sperm fertilization.
(More? Week 1 Notes)
PCBs, a class of chemicals linked to developmental defects.
(More? Defects - Chemical Notes)
(PRE/TREs) cis-regulatory DNA elements initiator elements and maintenance elements identified in drosophila development. They can activate or silence transcriptional state of associated genes for many cell generations (divisions).
(More? PubMed Review)
polysialic acid
(PSA) is a cell surface carbohydrate attached to neural cell adhesion molecule (NCAM) that regulates (inhibits) cell interactions. During development PSA has a role in promoting neural precursor cell migration and axon path-finding.
(More? PNAS Image)
(PCOS) or Stein-Leventhal syndrome (1930s researchers) a metabolic syndrome with many other symptoms, ovarian cysts arise through incomplete follicular development or failure of ovulation.
(More? Urogenital Abnormalities)
(polydactylia or polydactylism) developmental abnormality resulting in an additional fingers or toes. Occasional there is aslo a combination of polydactyly with syndactyly is known as polysyndactyly.
(More? Limb Abnormalities)
polysyndactyly
abnormal digit (finger or toe) development resulting in a combination of polydactyly (additional digit) with syndactyly (digit fusion).
(More? Limb Abnormalities)
postmature
term used to describe infants born after 42 weeks clinical gestation. Normal clinical gestation is 40 weeks (which is usually 36-38 weeks embryonic development) infants born before 37 weeks are called premature.
(More? Normal Development - Birth)
precocial species
newborn animals that are relatively mature and mobile from birth or hatching, for example guinea pigs and hoofed animals. (altricial is where newborns are immature and not motile).
preeclampsia
(toxemia, pregnancy-induced hypertension) high blood pressure and protein in the urine which can occur during pregnancy and may lead to eclampsia, a serious maternal condition leading to seizures or coma.
(More? Placenta | Medline Plus - preeclampsia eMJA - Pre-eclampsia: a lifelong disorder)
pregnancy-associated plasma protein-A
(PAPP-A) This placental protein is thought to have several different functions, including preventing recognition of the fetus by the maternal immune system, matrix mineralization and angiogenesis. It is a member of the alpha-macroglobulin plasma protein family, which bind cytokines and specifically cleave a binding protein for insulin-like growth factors (IGF binding protein 4 protease) modulating cytokine activity. Detection of this protein is also used as a first and second trimester diagnostic test for Trisomy 21.
(More? Abnormal Development - Prenatal Diagnosis - PAPP-A | Abnormal Development - Trisomy 21 (Down Syndrome) | Placenta Notes)
pregnancy (clinical)
pregnancy verified by the presence of a gestational sac on ultrasound.
(More? Week 1 Notes)
pre-implantation genetic diagnosis
(PGD) a screening procedure for embryos produced through in vitro fertilisation (IVF) for genetic diseases that would generate developmental abnormalities or serious postnatal diseases.
(More? Week 1 Notes | In Vitro Fertilization Notes)
premature
term used to describe infants born before 37 weeks. Normal clinical gestation is 40 weeks (which is usually 36-38 weeks embryonic development) infants born after 42 weeks clinical gestation are called postmature.
(More? Normal Development - Birth)
Pre-Menstrual Syndrome
a diverse range of symptoms that appear before menstruation, which apparently occur due to changing levels of sex hormones (progesterone, estrogen) and progesterone's metabolite (alopregnanolone) during the menstrual cycle. The possible PMS symptoms: tiredness, depression, restlessness, insomnia, irritability, emotional, outbursts of anger, headache, dizziness, abdominal pain, breast pain, water retention, diarrhoea, increase in appetite and food craving (sugar, salt). Women can show some or all of these symptoms.
(More? Human Menstrual Cycle | ABC RN Monday 8 June 1998 - Premenstrual Syndrome)
presentation
birth term, referring to how the fetus is situated in the uterus at the time of birth.
(More? Normal Development - Birth)
presenting part
birth term, referring to the part of fetus body that is closest to the cervix.
(More? Normal Development - Birth)
prevalence
statistical term used mainly in studying disease/disorders and is a measure of the proportion of a population that are disease cases at a point in time. Generally used to measure only relatively stable conditions, not suitable for acute disorders.
(More? Abnormal Development)
primary organizer
The term used by Spemann to describe the dorsal lip of the blastopore, meaning that its action established the organization of the entire early embryo. (see primitive node | Hans Spemann | Nobel Laureate- Hans Spemann)
primitive node
(= Hensen's Node, primitive knot) forms the initial region at the cranial end of the primitive streak (where gastrulation occurs) and is a controller of this process. It is also the site of epiblast extension cranially to form the initial axial process. Region is equivilant to the blastopore in amphibians.
(More? Carnegie Stage 7 | Week 3 Gastrulation | Neural Notes | Nobel Laureate- Hans Spemann)
primitive streak
Region visible on the surface of the early epiblast embryonic disc showing the region where gastrulation (cell migration to form endoderm) is occurring. In the human embryo this process occurs from week 3 through week 4.
(More? Carnegie Stage 7 | Week 3 Gastrulation)
primordial follicle
Present in the ovary from birth, located in the stroma of the ovary cortex beneath the tunica albuginea. The primordial follicle is the oocyte and the surrounding follicular cells.
(More? Week 1 Notes)
primordial germ cell
either the sperm progenitor in the embryonic testes or oocyte progenitor present in the primordial follicle ovary from birth, located in the stroma of the ovary cortex beneath the tunica albuginea. The primordial follicle is the oocyte and the surrounding follicular cells. (More? Week 1 Notes)
a transient communicating channel in testes development between tunica vaginalis and peritoneal cavity.
(More? Urogenital Notes)
(PRL) anterior pituitary hormone which stimulates breast development and milk production in pregnancy. Also has a role in regulating follicle stimulating hormone (FSH) effect on the ovary. Protein hormone is similar in structure to both growth hormone (anterior pituitary) and chorionic somatomammotropin (placenta). Anterior pituitary release of prolactin is in turn regulated by the hypothalamus prolactin-releasing hormone (PRLH, prolactin-releasing peptide). Recently been shown to to mimic in pregnancy effects of increased maternal myelination processes (oligodendrocyte precursor proliferation).
(More? Endocrine Development - Pituitary | Normal Development - Milk | OMIM - PRL)
(PRLH, prolactin-releasing peptide, PRRP) an 87 amino acid peptide hypothalamus hormone which regulates anterior pituitary release of prolactin.
pronephros
(Greek, pro = before) the first temporary stage of kidney development (pro-, meso-, meta-). This forms the kidney of fish. In humans, very rudimentary and rapidly replaced by mesonephros.
(More? Urogenital Notes)
propatagium
is the thin skin membrane (extending from the shoulder to the wrist anterior to the upper arm and forearm) forming the leading edge of the bat wing.
(More? Other Embryos - Bat)
(Greek, pro = before) The first phase of mitosis, when the diffusely stained chromatin resolves into discrete chromosomes, each consisting of two chromatids joined together at the centromere.
(More? Week 1 Notes)
a large multiprotein complex found in all cells that functions in degradation of ubiquitylated proteins.
(More? UNSW Cell Biology)
(Latin, prurire = to itch) itching skin sensation which can have a number of different causes (diabetes, iron deficiency, hyperthyroidism, Hodgkin's Disease, hair loss, allergic drug reaction).
(More? Skin Notes)
puberty
(Latin, pubertas = adulthood) process involving maturation of the reproductive system. A complex process, initiated by an unknown mechanism, but involving the brain driving the hormonal axis.
(More? Endocrine Notes - Gonad | Puberty Notes)
pertaining to childbirth or the period immediately following birth.
(More? Birth Notes)
six weeks following parturition (birth). Maternal reproductive organs and physiology return to pre-pregnant state.
(More? Birth Notes)
dilatation of the fetal renal pelvis (anteroposterior pelvic diameter >/=4 mm) visible with ultrasound.
(More? Kidney Notes | Movies - Abnormal Ultrasound)
(Greek, pyknon = dense) term used to describe a DNA non-random pattern of repeated sequence elements identified in the human genome following computer analysis (genic and nongenic regions, patterns of 16+ bases in length, occurring 40+ times in nongenic). These sequences are: found frequently in the 3' untranslated regions (3'UTR) of genes, can be repeated with a regular spacing of 18 to 22 nucleotides between copies, and have currently an unknown function.
a type II membrane glycoprotein component found in fenestrae and in caveolae.
(More? Stan RV, Kubitza M, Palade GE. PV-1 is a component of the fenestral and stomatal diaphragms in fenestrated endothelia. Proc Natl Acad Sci U S A. 1999 Nov 9;96(23):13203-7.)
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Search the NIH Medlineplus Medical Dictionary Type the word that you would like to find. If unsure of spelling, type the first few letters, followed by an asterisk(*). |
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Use this page to access brief definitions of specific alphabetically listed 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 Glossary List: Texts listed on page 1 Reading of each notes section, Department of Anatomy Publications, WWW resources from NCBI, AMA (USA), Office of Rare Diseases (USA), PubMed Medline Dictionaries, MSDS, Merck Manual home edn., NHMRC (Australia). 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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