Redalyc.From Hatching Into Fetal Life in The
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3 Embryology and Development
BIOL 6505 − INTRODUCTION TO FETAL MEDICINE 3. EMBRYOLOGY AND DEVELOPMENT Arlet G. Kurkchubasche, M.D. INTRODUCTION Embryology – the field of study that pertains to the developing organism/human Basic embryology –usually taught in the chronologic sequence of events. These events are the basis for understanding the congenital anomalies that we encounter in the fetus, and help explain the relationships to other organ system concerns. Below is a synopsis of some of the critical steps in embryogenesis from the anatomic rather than molecular basis. These concepts will be more intuitive and evident in conjunction with diagrams and animated sequences. This text is a synopsis of material provided in Langman’s Medical Embryology, 9th ed. First week – ovulation to fertilization to implantation Fertilization restores 1) the diploid number of chromosomes, 2) determines the chromosomal sex and 3) initiates cleavage. Cleavage of the fertilized ovum results in mitotic divisions generating blastomeres that form a 16-cell morula. The dense morula develops a central cavity and now forms the blastocyst, which restructures into 2 components. The inner cell mass forms the embryoblast and outer cell mass the trophoblast. Consequences for fetal management: Variances in cleavage, i.e. splitting of the zygote at various stages/locations - leads to monozygotic twinning with various relationships of the fetal membranes. Cleavage at later weeks will lead to conjoined twinning. Second week: the week of twos – marked by bilaminar germ disc formation. Commences with blastocyst partially embedded in endometrial stroma Trophoblast forms – 1) cytotrophoblast – mitotic cells that coalesce to form 2) syncytiotrophoblast – erodes into maternal tissues, forms lacunae which are critical to development of the uteroplacental circulation. -
Development and Maintenance of Epidermal Stem Cells in Skin Adnexa
International Journal of Molecular Sciences Review Development and Maintenance of Epidermal Stem Cells in Skin Adnexa Jaroslav Mokry * and Rishikaysh Pisal Medical Faculty, Charles University, 500 03 Hradec Kralove, Czech Republic; [email protected] * Correspondence: [email protected] Received: 30 October 2020; Accepted: 18 December 2020; Published: 20 December 2020 Abstract: The skin surface is modified by numerous appendages. These structures arise from epithelial stem cells (SCs) through the induction of epidermal placodes as a result of local signalling interplay with mesenchymal cells based on the Wnt–(Dkk4)–Eda–Shh cascade. Slight modifications of the cascade, with the participation of antagonistic signalling, decide whether multipotent epidermal SCs develop in interfollicular epidermis, scales, hair/feather follicles, nails or skin glands. This review describes the roles of epidermal SCs in the development of skin adnexa and interfollicular epidermis, as well as their maintenance. Each skin structure arises from distinct pools of epidermal SCs that are harboured in specific but different niches that control SC behaviour. Such relationships explain differences in marker and gene expression patterns between particular SC subsets. The activity of well-compartmentalized epidermal SCs is orchestrated with that of other skin cells not only along the hair cycle but also in the course of skin regeneration following injury. This review highlights several membrane markers, cytoplasmic proteins and transcription factors associated with epidermal SCs. Keywords: stem cell; epidermal placode; skin adnexa; signalling; hair pigmentation; markers; keratins 1. Epidermal Stem Cells as Units of Development 1.1. Development of the Epidermis and Placode Formation The embryonic skin at very early stages of development is covered by a surface ectoderm that is a precursor to the epidermis and its multiple derivatives. -
AP-2Α and AP-2Β Cooperatively Function in the Craniofacial Surface Ectoderm to Regulate
bioRxiv preprint doi: https://doi.org/10.1101/2021.06.10.447717; this version posted June 10, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. AP-2α and AP-2β cooperatively function in the craniofacial surface ectoderm to regulate 2 chromatin and gene expression dynamics during facial development. 4 Eric Van Otterloo1,2,3,4,*, Isaac Milanda4, Hamish Pike4, Hong Li4, Kenneth L Jones5#, Trevor Williams4,6,7,* 6 1 Iowa Institute for Oral Health Research, College of Dentistry & Dental Clinics, University of Iowa, Iowa City, IA, 52242, USA 8 2 Department of Periodontics, College of Dentistry & Dental Clinics, University of Iowa, Iowa City, IA, 52242, USA 10 3 Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA 12 4 Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA 14 5 Department of Pediatrics, Section of Hematology, Oncology, and Bone Marrow Transplant, University of Colorado School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, 16 USA 6 Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, 18 Aurora, CO, 80045, USA 7 Department of Pediatrics, University of Colorado Anschutz Medical Campus, Children's Hospital 20 Colorado, Aurora, CO 80045, USA * Corresponding Authors 22 #Present Address: Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA 24 Keywords: Tfap2, AP-2, transcription factor, ectoderm, craniofacial, neural crest, Wnt signaling 26 bioRxiv preprint doi: https://doi.org/10.1101/2021.06.10.447717; this version posted June 10, 2021. -
Determination of Cell Development, Differentiation and Growth
Pediat. Res. I: 395-408 (1967) Determination of Cell Development, Differentiation and Growth A Review D.M.BROWN[ISO] Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, USA Introduction plasmic synthesis, water uptake, or, in the case of intact tissue, intercellular deposition. It may include prolifera It has become increasingly apparent that the basis for tion or the multiplication of identical cells and may be biologic variation in relation to disease states is in accompanied by differentiation which implies anatomical large part predetermined from early embryonic stages. as well as functional changes. The number of cellular Consideration of variations of growth and development units in a tissue may be related to the deoxyribonucleic must take into account the genetic constitution and acid (DNA) content or nucleocytoplasmic units [24, early embryonic events of tissue and organ develop 59, 143]. Differentiation may refer to physical and ment. chemical organization of subcellular components or The incidence of congenital malformation has been to changes in the structure and organization of cells estimated to be 2 to 3 percent of all live born infants and leading to specialized organs. may double by one year [133]. Minor abnormalities are even more common [79]. Furthermore, the large variety of well-defined 'inborn errors of metabolism', Control of Embryonic Chemical Development as well as the less apparent molecular and chromosomal abnormalities, should no doubt be considered as mal Protein syntheses during oogenesis and embryogenesis formations despite the possible lack of gross somatic are guided by nuclear and nucleolar ribonucleic acid aberrations. Low birth weight is a frequent accom (RNA) which are in turn controlled by primer DNA. -
Lecture 19 Placentation and Maternal Recognition of Pregnancy
Blastulation Gap Junctions Lecture 19 Inner Cell Mass Zona Pellucida Placentation and Maternal Recognition of Pregnancy Trophectoderm Na+ [Na+] Animal Science 434 John J. Parrish H2O Tight Junctions Hatching Conceptus Growth Cow • Day 15, 1-2 mm Occurs in cow, pig and sheep Bovine • Day 18-19, 10-20 cm »9 - 11 days Spherical Embryonic Equine, Ovine Area »7 - 8 days Porcine Tubular Elongating »6 days Trophoblast Filamentous Mare remains spherical! Development of Porcine Conceptuses Elongated Day 15 Porcine from Day 10 to 12 Conceptus 5 mm Spherical 10 mm Spherical Inner Cell Mass 15 mm Tubular 150 mm Filamentous Embryo 1 Uterine Location of Elongating Pig Intrauterine Migration Ruminant Blastocyst Day 5 Corpus Luteum Bovine and Ovine Pig Intrauterine Migration Pig Intrauterine Migration Day 7 Day 12 Embryos become fixed Transuterine migration is rare in cow and ewe! Trans-uterine Migration in the Mare Gastrulation Begins Day 10 Inner Cell Mass Trophectoderm Formation Endoderm of Germ Fixation can Fixation occur in either on day Layers horn! 15 - 16 Blastocoele Corpus Cavity Luteum 2 Gastrulation Gastrulation Endoderrm Endoderrm Yolk Sack Yolk Sack Gastrula Gastrula Ectoderm Ectoderm Mesoderm Ectoderm Trophectoderm Trophectoderm Extraembryonic Coelom Yolk Sack Endoderm Endoderm Trophectoderm (Chorion) Germ Layers Placenta Formation Embryonic Amniotic Folds Ectoderm Mesoderm Endoderm Ectoderm » CNS » Circulatory » Digestive » Sense organs » Skeletal » Liver » Mammary » Muscle » Lungs glands » Reproductive » Pancreas Extraembryonic » -
Quain's Anatomy
ism v-- QuAiN's Anatomy 'iC'fi /,'' M.:\ ,1 > 111 ,t*, / Tj ^f/' if ^ y} 'M> E. AoeHAEER k G. D. THANE dJorneU Hntttcraitg Ilihrarg Stiiatu. ^tm fotk THE CHARLES EDWARD VANCLEEF MEMORIAL LIBRARY SOUGHT WITH THE mCOME OF A FUND GIVEN FOR THE USE OF THE ITHACA DIVISION OF THE CORNELL UNIVERSITY MEDICAL COLLEGE MYNDERSE VAN CLEEF CLASS OF 1674 I9ZI Cornell University Library QM 23.Q21 1890 v.1,pL1 Quain's elements of anatomy.Edited by Ed 3 1924 003 110 834 t€ Cornell University Library The original of tiiis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003110834 QUAIN'S ELEMENTS OF ANATOMY EDITED BY EDWAED ALBERT SCHAFEE, F.E.S. PROFESSOR OF PHYSIOLOnV AND niSTOLOOY IN UNIVERSITY COLLEGE, LONDON^ GEOEGE DANCEE THANE, PROFESSOR OF ANATOMY IN UNIVERSITY COLLEGE, LONDON. IN. TflE:^VO£iTSME'S!f VOL. L—PAET I. EMBRYOLOGY By professor SCHAFER. illustrated by 200 engravings, many of which are coloured. REPRINTED FROM THE ^Centlj ffiiittion. LONGMANS, GREEN, AND CO. LONDON, NEW YORK, AND BOMBAY 1896 [ All rights reserved ] iDBUKV, ACNEW, & CO. LD., fRINTEKS, WllITEr KIARS.P^7> ^^fp CONTENTS OF PART I. IV CONTKNTS OF TAKT I. page fifth Formation of the Anus . io8 Destination of the fourth and Arte Formation of the Glands of the Ali- rial Arches ISO MKNTAKT CaNAL .... 109 Development of the principal Veins. 151 fcetal of Circu- The Lungs , . 109 Peculiarities of the Organs The Trachea and Larynx no lation iSS The Thyroid Body .. -
Vocabulario De Morfoloxía, Anatomía E Citoloxía Veterinaria
Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) Servizo de Normalización Lingüística Universidade de Santiago de Compostela COLECCIÓN VOCABULARIOS TEMÁTICOS N.º 4 SERVIZO DE NORMALIZACIÓN LINGÜÍSTICA Vocabulario de Morfoloxía, anatomía e citoloxía veterinaria (galego-español-inglés) 2008 UNIVERSIDADE DE SANTIAGO DE COMPOSTELA VOCABULARIO de morfoloxía, anatomía e citoloxía veterinaria : (galego-español- inglés) / coordinador Xusto A. Rodríguez Río, Servizo de Normalización Lingüística ; autores Matilde Lombardero Fernández ... [et al.]. – Santiago de Compostela : Universidade de Santiago de Compostela, Servizo de Publicacións e Intercambio Científico, 2008. – 369 p. ; 21 cm. – (Vocabularios temáticos ; 4). - D.L. C 2458-2008. – ISBN 978-84-9887-018-3 1.Medicina �������������������������������������������������������������������������veterinaria-Diccionarios�������������������������������������������������. 2.Galego (Lingua)-Glosarios, vocabularios, etc. políglotas. I.Lombardero Fernández, Matilde. II.Rodríguez Rio, Xusto A. coord. III. Universidade de Santiago de Compostela. Servizo de Normalización Lingüística, coord. IV.Universidade de Santiago de Compostela. Servizo de Publicacións e Intercambio Científico, ed. V.Serie. 591.4(038)=699=60=20 Coordinador Xusto A. Rodríguez Río (Área de Terminoloxía. Servizo de Normalización Lingüística. Universidade de Santiago de Compostela) Autoras/res Matilde Lombardero Fernández (doutora en Veterinaria e profesora do Departamento de Anatomía e Produción Animal. -
The Genetic Basis of Mammalian Neurulation
REVIEWS THE GENETIC BASIS OF MAMMALIAN NEURULATION Andrew J. Copp*, Nicholas D. E. Greene* and Jennifer N. Murdoch‡ More than 80 mutant mouse genes disrupt neurulation and allow an in-depth analysis of the underlying developmental mechanisms. Although many of the genetic mutants have been studied in only rudimentary detail, several molecular pathways can already be identified as crucial for normal neurulation. These include the planar cell-polarity pathway, which is required for the initiation of neural tube closure, and the sonic hedgehog signalling pathway that regulates neural plate bending. Mutant mice also offer an opportunity to unravel the mechanisms by which folic acid prevents neural tube defects, and to develop new therapies for folate-resistant defects. 6 ECTODERM Neurulation is a fundamental event of embryogenesis distinct locations in the brain and spinal cord .By The outer of the three that culminates in the formation of the neural tube, contrast, the mechanisms that underlie the forma- embryonic (germ) layers that which is the precursor of the brain and spinal cord. A tion, elevation and fusion of the neural folds have gives rise to the entire central region of specialized dorsal ECTODERM, the neural plate, remained elusive. nervous system, plus other organs and embryonic develops bilateral neural folds at its junction with sur- An opportunity has now arisen for an incisive analy- structures. face (non-neural) ectoderm. These folds elevate, come sis of neurulation mechanisms using the growing battery into contact (appose) in the midline and fuse to create of genetically targeted and other mutant mouse strains NEURAL CREST the neural tube, which, thereafter, becomes covered by in which NTDs form part of the mutant phenotype7.At A migratory cell population that future epidermal ectoderm. -
Embryology J
Embryology J. Matthew Velkey, Ph.D. [email protected] 452A Davison, Duke South Textbook: Langmans’s Medical Embryology, 11th ed. When possible, lectures will be recorded and there may be notes for some lectures, but still NOT a substitute for reading the text. Completing assigned reading prior to class is essential for sessions where a READINESS ASSESSMENT is scheduled. Overall goal: understand the fundamental processes by which the adult form is produced and the clinical consequences that arise from abnormal development. Follicle Maturation and Ovulation Oocytes ~2 million at birth ~40,000 at puberty ~400 ovulated over lifetime Leutinizing Hormone surge (from pituitary gland) causes changes in tissues and within follicle: • Swelling within follicle due to increased hyaluronan • Matrix metalloproteinases degrade surrounding tissue causing rupture of follicle Egg and surrounding cells (corona radiata) ejected into peritoneum Corona radiata provides bulk to facilitate capture of egg. The egg (and corona radiata) at ovulation Corona radiata Zona pellucida (ZP-1, -2, and -3) Cortical granules Transport through the oviduct At around the midpoint of the menstrual cycle (~day 14), a single egg is ovulated and swept into the oviduct. Fertilization usually occurs in the ampulla of the oviduct within 24 hrs. of ovulation. Series of cleavage and differentiation events results in the formation of a blastocyst by the 4th embryonic day. Inner cell mass generates embryonic tissues Outer trophectoderm generates placental tissues Implantation into -
Urinary System Intermediate Mesoderm
Urinary System Intermediate mesoderm lateral mesoderm: somite ectoderm neural NOTE: Intermediate mesoderm splanchnic groove somatic is situated between somites and lateral mesoderm (somatic and splanchnic mesoderm bordering the coelom). All mesoderm is derived from the primary mesen- intermediate mesoderm endoderm chyme that migrated through the notochord coelom (becomes urogenital ridge) primitive streak. Intermediate mesoderm (plus adjacent mesothelium lining the coelom) forms a urogenital ridge, which consists of a laterally-positioned nephrogenic cord (that forms kidneys & ureter) and a medially-positioned gonadal ridge (for ovary/testis & female/male genital tract formation). Thus urinary & genital systems have a common embryonic origin; also, they share common ducts. NOTE: Urine production essentially requires an increased capillary surface area (glomeruli), epithelial tubules to collect plasma filtrate and extract desirable constituents, and a duct system to convey urine away from the body. Kidneys Bilateraly, three kid- mesonephric duct neys develop from the neph- metanephros pronephros rogenic cord. They develop mesonephric tubules chronologically in cranial- mesonephros caudal sequence, and are designated pro—, meso—, Nephrogenic Cord (left) and meta—, respectively. cloaca The pronephros and mesonephros develop similarly: the nephrogenic cord undergoes seg- mentation, segments become tubules, tubules drain into a duct & eventually tubules disintegrate. spinal ganglion 1] Pronephros—consists of (7-8) primitive tubules and a pronephric duct that grows caudally and terminates in the cloaca. The tubules soon degenerate, but the pronephric duct persists as the neural tube mesonephric duct. (The pronephros is not functional, somite except in sheep.) notochord mesonephric NOTE tubule The mesonephros is the functional kidney for fish and am- aorta phibians. The metanephros is the functional kidney body of reptiles, birds, & mammals. -
The Derivatives of Three-Layered Embryo (Germ Layers)
HUMANHUMAN EMBRYOLOGYEMBRYOLOGY Department of Histology and Embryology Jilin University ChapterChapter 22 GeneralGeneral EmbryologyEmbryology FourthFourth week:week: TheThe derivativesderivatives ofof trilaminartrilaminar germgerm discdisc Dorsal side of the germ disc. At the beginning of the third week of development, the ectodermal germ layer has the shape of a disc that is broader in the cephalic than the caudal region. Cross section shows formation of trilaminar germ disc Primitive pit Drawing of a sagittal section through a 17-day embryo. The most cranial portion of the definitive notochord has formed. ectoderm Schematic view showing the definitive notochord. horizon =ectoderm hillside fields =neural plate mountain peaks =neural folds Cave sinks into mountain =neural tube valley =neural groove 7.1 Derivatives of the Ectodermal Germ Layer 1) Formation of neural tube Notochord induces the overlying ectoderm to thicken and form the neural plate. Cross section Animation of formation of neural plate When notochord is forming, primitive streak is shorten. At meanwhile, neural plate is induced to form cephalic to caudal end, following formation of notochord. By the end of 3rd week, neural folds and neural groove are formed. Neural folds fuse in the midline, beginning in cervical region and Cross section proceeding cranially and caudally. Neural tube is formed & invade into the embryo body. A. Dorsal view of a human embryo at approximately day 22. B. Dorsal view of a human embryo at approximately day 23. The nervous system is in connection with the amniotic cavity through the cranial and caudal neuropores. Cranial/anterior neuropore Neural fold heart Neural groove endoderm caudal/posterior neuropore A. -
Paraxial Mesoderm)
By DR. SANAA ALSHAARAWY DR. ESSAM ELDIN SALAMA OBJECTIVES : At the end of the lecture, the student should be able to describe : Changes in the bilaminar germ disc (embryonic plate). Formation of the secondary embryonic mesoderm (intraembryonic mesoderm). Formation of trilaminar germ disc. Formation of the primitive streake & notochord. Differantiation of intra-embryonic mesoderm. Implantation of the blastocyst is completed by the end of the 2nd week . As this process occurs, changes occur in the embryoblast that produce a bilaminar embryonic disc. The embryonic disc gives rise to the germ layers that form all tissues & organs of the embryo. Extraembryonic structures forming during the 2nd week are : the amniotic cavity, amnion, yolk sac, and connecting stalk. By the (8th) day: The Inner Cell Mass (Embryoblast)is differentiated into a bilaminar plate of cells composed of Two layers : (A) Epiblast High columnar cells adjacent to the amniotic cavity. (B) Hypoblast Small cuboidal cells adjacent to the blastocyst cavity (Yolk Sac). A loose connective tissue, arises from the yolk sac. It fills all the space between the trophoblast externally and the exocoelomic membrane & amnion internally. It surrounds the amnion and yolk sac. Multiple spaces appear within the Extraembryonic mesoderm. These spaces fuse and form the Extraembryonic Coelom. It surrounds the amnion and yolk sac. It is the process through which the Bilaminar embryonic disc is changed into a Trilaminar disc, as a new tissue (2ry or intraembryonic mesoderm) appears between the ectoderm and endoderm. Now the embryonic disc is formed of 3 layers: Embryonic Ectoderm Intraembryonic Mesoderm. Embryonic Endoderm. Cells in these layers will give rise to all tissues and organs of the embryo.