Gastrulation, the Glossary
Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells), or in mammals the blastocyst, is reorganized into a two-layered or three-layered embryo known as the gastrula.[1]
Table of Contents
119 relations: Amniote, Anatomical terms of location, Animal, Animal embryonic development, Anus, Archenteron, Asymmetry, Blastocoel, Blastocyst, Blastulation, Blood, Blood vessel, Bone, Bone morphogenetic protein, Bone morphogenetic protein 4, Cadherin-1, Cartilage, Catenin beta-1, Cell (biology), Cell adhesion, Cell culture, Cell lineage, Cellular differentiation, Cerberus (protein), Chicken, Cleavage (embryo), Cnidaria, Connective tissue, Ctenophora, Cytoplasm, Cytoskeleton, Dermis, Deuterostome, Developmental biology, Digestion, Diploblasty, Dorsal lip, Ectoderm, Embryo, Embryoid body, Embryological origins of the mouth and anus, Embryonic stem cell, Endoderm, Epiblast, Epiboly, Epidermis (zoology), Epithelial–mesenchymal transition, Epithelium, Ernst Haeckel, Fate mapping, ... Expand index (69 more) »
Amniote
Amniotes are tetrapod vertebrate animals belonging to the clade Amniota, a large group that comprises the vast majority of living terrestrial and semiaquatic vertebrates.
Anatomical terms of location
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans.
See Gastrulation and Anatomical terms of location
Animal
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia.
Animal embryonic development
In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Gastrulation and animal embryonic development are embryology.
See Gastrulation and Animal embryonic development
Anus
In mammals, invertebrates and most fish, the anus (anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the exit end of the digestive tract (bowel), i.e. the opposite end from the mouth.
Archenteron
The archenteron, also called the gastrocoel, the primitive digestive tube or the primitive gut, is the internal cavity of the primitive gastrointestinal tract that forms during gastrulation in a developing animal embryo. Gastrulation and archenteron are animal developmental biology.
See Gastrulation and Archenteron
Asymmetry
Asymmetry is the absence of, or a violation of, symmetry (the property of an object being invariant to a transformation, such as reflection).
See Gastrulation and Asymmetry
Blastocoel
The blastocoel, also spelled blastocoele and blastocele, and also called cleavage cavity, or segmentation cavity is a fluid-filled or yolk-filled cavity that forms in the blastula during very early embryonic development. Gastrulation and blastocoel are animal developmental biology.
See Gastrulation and Blastocoel
Blastocyst
The blastocyst is a structure formed in the early embryonic development of mammals. Gastrulation and blastocyst are embryology.
See Gastrulation and Blastocyst
Blastulation
Blastulation is the stage in early animal embryonic development that produces the blastula. Gastrulation and Blastulation are animal developmental biology.
See Gastrulation and Blastulation
Blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells.
Blood vessel
Blood vessels are the structures of the circulatory system that transport blood throughout the human body.
See Gastrulation and Blood vessel
Bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals.
Bone morphogenetic protein
Bone morphogenetic proteins (BMPs) are a group of growth factors also known as cytokines and as metabologens. Gastrulation and Bone morphogenetic protein are animal developmental biology.
See Gastrulation and Bone morphogenetic protein
Bone morphogenetic protein 4
Bone morphogenetic protein 4 is a protein that in humans is encoded by BMP4 gene.
See Gastrulation and Bone morphogenetic protein 4
Cadherin-1
Cadherin-1 or Epithelial cadherin (E-cadherin), (not to be confused with the APC/C activator protein CDH1) is a protein that in humans is encoded by the CDH1 gene.
See Gastrulation and Cadherin-1
Cartilage
Cartilage is a resilient and smooth type of connective tissue.
See Gastrulation and Cartilage
Catenin beta-1
Catenin beta-1, also known as β-catenin (beta-catenin), is a protein that in humans is encoded by the CTNNB1 gene.
See Gastrulation and Catenin beta-1
Cell (biology)
The cell is the basic structural and functional unit of all forms of life.
See Gastrulation and Cell (biology)
Cell adhesion
Cell adhesion is the process by which cells interact and attach to neighbouring cells through specialised molecules of the cell surface.
See Gastrulation and Cell adhesion
Cell culture
Cell culture or tissue culture is the process by which cells are grown under controlled conditions, generally outside of their natural environment.
See Gastrulation and Cell culture
Cell lineage
Cell lineage denotes the developmental history of a tissue or organ from the fertilized egg.
See Gastrulation and Cell lineage
Cellular differentiation
Cellular differentiation is the process in which a stem cell changes from one type to a differentiated one.
See Gastrulation and Cellular differentiation
Cerberus (protein)
Cerberus is a protein that in humans is encoded by the CER1 gene.
See Gastrulation and Cerberus (protein)
Chicken
The chicken (Gallus domesticus) is a large and round short-winged bird, domesticated from the red junglefowl of Southeast Asia around 8,000 years ago. Most chickens are raised for food, providing meat and eggs; others are kept as pets or for cockfighting. Chickens are common and widespread domestic animals, with a total population of 23.7 billion, and an annual production of more than 50 billion birds.
Cleavage (embryo)
In embryology, cleavage is the division of cells in the early development of the embryo, following fertilization.
See Gastrulation and Cleavage (embryo)
Cnidaria
Cnidaria is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in fresh water and marine environments (predominantly the latter), including jellyfish, hydroids, sea anemones, corals and some of the smallest marine parasites.
Connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue.
See Gastrulation and Connective tissue
Ctenophora
Ctenophora (ctenophore) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide.
See Gastrulation and Ctenophora
Cytoplasm
In cell biology, the cytoplasm describes all material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus.
See Gastrulation and Cytoplasm
Cytoskeleton
The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea.
See Gastrulation and Cytoskeleton
Dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain.
Deuterostome
Deuterostomes (from Greek) are bilaterian animals of the superphylum Deuterostomia, typically characterized by their anus forming before the mouth during embryonic development.
See Gastrulation and Deuterostome
Developmental biology
Developmental biology is the study of the process by which animals and plants grow and develop.
See Gastrulation and Developmental biology
Digestion
Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma.
See Gastrulation and Digestion
Diploblasty
Diploblasty is a condition of the blastula in which there are two primary germ layers: the ectoderm and endoderm.
See Gastrulation and Diploblasty
Dorsal lip
The dorsal lip of the blastopore is a structure that forms during early embryonic development and is important for its role in organizing the germ layers. Gastrulation and dorsal lip are animal developmental biology and embryology.
See Gastrulation and Dorsal lip
Ectoderm
The ectoderm is one of the three primary germ layers formed in early embryonic development. Gastrulation and ectoderm are animal developmental biology and embryology.
Embryo
An embryo is the initial stage of development for a multicellular organism. Gastrulation and embryo are embryology.
Embryoid body
Embryoid bodies (EBs) are three-dimensional aggregates formed by pluripotent stem cells.
See Gastrulation and Embryoid body
Embryological origins of the mouth and anus
The embryological origin of the mouth and anus is an important characteristic, and forms the morphological basis for separating bilaterian animals into two natural groupings: the protostomes and deuterostomes.
See Gastrulation and Embryological origins of the mouth and anus
Embryonic stem cell
Embryonic stem cells (ESCs) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage pre-implantation embryo. Gastrulation and Embryonic stem cell are embryology.
See Gastrulation and Embryonic stem cell
Endoderm
Endoderm is the innermost of the three primary germ layers in the very early embryo. Gastrulation and Endoderm are embryology.
Epiblast
In amniote embryonic development, the epiblast (also known as the primitive ectoderm) is one of two distinct cell layers arising from the inner cell mass in the mammalian blastocyst, or from the blastula in reptiles and birds, the other layer is the hypoblast. Gastrulation and epiblast are embryology.
Epiboly
Epiboly describes one of the five major types of cell movements that occur in the gastrulation stage of embryonic development of some organisms.
Epidermis (zoology)
In zoology, the epidermis is an epithelium (sheet of cells) that covers the body of a eumetazoan (animal more complex than a sponge).
See Gastrulation and Epidermis (zoology)
Epithelial–mesenchymal transition
The epithelial–mesenchymal transition (EMT) is a process by which epithelial cells lose their cell polarity and cell–cell adhesion, and gain migratory and invasive properties to become mesenchymal stem cells; these are multipotent stromal cells that can differentiate into a variety of cell types. Gastrulation and epithelial–mesenchymal transition are animal developmental biology.
See Gastrulation and Epithelial–mesenchymal transition
Epithelium
Epithelium or epithelial tissue is a thin, continuous, protective layer of compactly packed cells with little extracellular matrix.
See Gastrulation and Epithelium
Ernst Haeckel
Ernst Heinrich Philipp August Haeckel (16 February 1834 – 9 August 1919) was a German zoologist, naturalist, eugenicist, philosopher, physician, professor, marine biologist and artist.
See Gastrulation and Ernst Haeckel
Fate mapping
Fate mapping is a method used in developmental biology to study the embryonic origin of various adult tissues and structures.
See Gastrulation and Fate mapping
Fibroblast growth factor
Fibroblast growth factors (FGF) are a family of cell signalling proteins produced by macrophages; they are involved in a wide variety of processes, most notably as crucial elements for normal development in animal cells.
See Gastrulation and Fibroblast growth factor
Fibroblast growth factor 8
Fibroblast growth factor 8 (FGF-8) is a protein that in humans is encoded by the FGF8 gene.
See Gastrulation and Fibroblast growth factor 8
Fibroblast growth factor receptor 1
Fibroblast growth factor receptor 1 (FGFR-1), also known as basic fibroblast growth factor receptor 1, fms-related tyrosine kinase-2 / Pfeiffer syndrome, and CD331, is a receptor tyrosine kinase whose ligands are specific members of the fibroblast growth factor family.
See Gastrulation and Fibroblast growth factor receptor 1
Frog
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (coming from the Ancient Greek ἀνούρα, literally 'without tail').
Gastrointestinal tract
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines.
See Gastrulation and Gastrointestinal tract
Gastruloid
Gastruloids are three dimensional aggregates of embryonic stem cells (ESCs) that, when cultured in specific conditions, exhibit an organization resembling that of an embryo. Gastrulation and Gastruloid are animal developmental biology.
See Gastrulation and Gastruloid
Genus
Genus (genera) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses.
Germ layer
A germ layer is a primary layer of cells that forms during embryonic development. Gastrulation and germ layer are embryology.
See Gastrulation and Germ layer
Hans Spemann
Hans Spemann (27 June 1869 – 9 September 1941) was a German embryologist who was awarded a Nobel Prize in Physiology or Medicine in 1935 for his student Hilde Mangold's discovery of the effect now known as embryonic induction, an influence, exercised by various parts of the embryo, that directs the development of groups of cells into particular tissues and organs.
See Gastrulation and Hans Spemann
Heart
The heart is a muscular organ found in most animals.
Hilde Mangold
Hilde Mangold (20 October 1898 – 4 September 1924) (née Proescholdt) was a German embryologist who was best known for her 1923 dissertation which was the foundation for her mentor, Hans Spemann's, 1935 Nobel Prize in Physiology or Medicine for the discovery of the embryonic organizer,Mangold, Hilde (Proescholdt) by Marilyn Bailey Ogilvie and Joy Dorothy Harvey in The Biographical Dictionary of Women in Science.
See Gastrulation and Hilde Mangold
Homeobox
A homeobox is a DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development.
Hypoblast
In amniote embryology, the hypoblast is one of two distinct layers arising from the inner cell mass in the mammalian blastocyst, or from the blastodisc in reptiles and birds. Gastrulation and hypoblast are embryology.
See Gastrulation and Hypoblast
Induced pluripotent stem cell
Induced pluripotent stem cells (also known as iPS cells or iPSCs) are a type of pluripotent stem cell that can be generated directly from a somatic cell.
See Gastrulation and Induced pluripotent stem cell
Ingression (biology)
Ingression is one of the many changes in the location or relative position of cells that takes place during the gastrulation stage of embryonic development.
See Gastrulation and Ingression (biology)
Invagination
Invagination is the process of a surface folding in on itself to form a cavity, pouch or tube.
See Gastrulation and Invagination
Involution (medicine)
Involution is the shrinking or return of an organ to a former size.
See Gastrulation and Involution (medicine)
Koller's sickle
In avian gastrulation, Koller's sickle is a local thickening of cells at the posterior edge of the upper layer of the area pellucida called the epiblast.
See Gastrulation and Koller's sickle
Lefty (protein)
Lefty (left-right determination factors) are a class of proteins that are closely related members of the TGF-beta superfamily of growth factors.
See Gastrulation and Lefty (protein)
Lewis Wolpert
Lewis Wolpert (19 October 1929 – 28 January 2021) was a South African-born British developmental biologist, author, and broadcaster.
See Gastrulation and Lewis Wolpert
Liver
The liver is a major metabolic organ exclusively found in vertebrate animals, which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and various other biochemicals necessary for digestion and growth.
Mechanisms of Development
Mechanisms of Development is a peer-reviewed scientific journal covering all aspects of developmental biology.
See Gastrulation and Mechanisms of Development
Mesenchyme
Mesenchyme is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone.
See Gastrulation and Mesenchyme
Mesoderm
The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. Gastrulation and mesoderm are embryology.
Messenger RNA
In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein.
See Gastrulation and Messenger RNA
Microtubule
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells.
See Gastrulation and Microtubule
Model organism
A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms.
See Gastrulation and Model organism
Mollusca
Mollusca is the second-largest phylum of invertebrate animals, after Arthropoda; members are known as molluscs or mollusks.
Mothers against decapentaplegic homolog 2
Mothers against decapentaplegic homolog 2, also known as SMAD family member 2 or SMAD2, is a protein that in humans is encoded by the SMAD2 gene.
See Gastrulation and Mothers against decapentaplegic homolog 2
Mothers against decapentaplegic homolog 3
Mothers against decapentaplegic homolog 3 also known as SMAD family member 3 or SMAD3 is a protein that in humans is encoded by the SMAD3 gene.
See Gastrulation and Mothers against decapentaplegic homolog 3
Mothers against decapentaplegic homolog 4
SMAD4, also called SMAD family member 4, Mothers against decapentaplegic homolog 4, or DPC4 (Deleted in Pancreatic Cancer-4) is a highly conserved protein present in all metazoans.
See Gastrulation and Mothers against decapentaplegic homolog 4
Mouth
The mouth is the body orifice through which many animals ingest food and vocalize.
Muscle
Muscle is a soft tissue, one of the four basic types of animal tissue.
Nature Reviews Molecular Cell Biology
Nature Reviews Molecular Cell Biology is a monthly peer-reviewed review journal published by Nature Portfolio.
See Gastrulation and Nature Reviews Molecular Cell Biology
Necessity and sufficiency
In logic and mathematics, necessity and sufficiency are terms used to describe a conditional or implicational relationship between two statements.
See Gastrulation and Necessity and sufficiency
Nervous system
In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body.
See Gastrulation and Nervous system
Neural crest
Neural crest cells are a temporary group of cells that arise from the embryonic ectoderm germ layer, and in turn give rise to a diverse cell lineage—including melanocytes, craniofacial cartilage and bone, smooth muscle, peripheral and enteric neurons and glia.
See Gastrulation and Neural crest
Neurulation
Neurulation refers to the folding process in vertebrate embryos, which includes the transformation of the neural plate into the neural tube.
See Gastrulation and Neurulation
Nodal homolog
Nodal homolog is a secretory protein that in humans is encoded by the NODAL gene which is located on chromosome 10q22.1.
See Gastrulation and Nodal homolog
Nodal signaling pathway
The Nodal signaling pathway is a signal transduction pathway important in regional and cellular differentiation during embryonic development. Gastrulation and Nodal signaling pathway are embryology.
See Gastrulation and Nodal signaling pathway
Notch signaling pathway
The Notch signaling pathway is a highly conserved cell signaling system present in most animals.
See Gastrulation and Notch signaling pathway
Notochord
In zoology and developmental anatomy, the notochord is an elastic, rod-like anatomical structure found in many deuterostomal animals.
See Gastrulation and Notochord
Organ (biology)
In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function.
See Gastrulation and Organ (biology)
Organogenesis
Organogenesis is the phase of embryonic development that starts at the end of gastrulation and continues until birth. Gastrulation and Organogenesis are embryology.
See Gastrulation and Organogenesis
Organoid
An organoid is a miniaturised and simplified version of an organ produced in vitro in three dimensions that mimics the key functional, structural, and biological complexity of that organ.
Pancreas
The pancreas is an organ of the digestive system and endocrine system of vertebrates.
Placenta
The placenta (placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation.
Polarity in embryogenesis
In developmental biology, an embryo is divided into two hemispheres: the animal pole and the vegetal pole within a blastula.
See Gastrulation and Polarity in embryogenesis
Primitive node
The primitive node (or primitive knot) is the organizer for gastrulation in most amniote embryos. Gastrulation and primitive node are animal developmental biology.
See Gastrulation and Primitive node
Primitive streak
The primitive streak is a structure that forms in the early embryo in amniotes. Gastrulation and primitive streak are animal developmental biology.
See Gastrulation and Primitive streak
Protostome
Protostomia is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development.
See Gastrulation and Protostome
Respiratory system
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants.
See Gastrulation and Respiratory system
Retinoic acid
Retinoic acid (used simplified here for all-trans-retinoic acid) is a metabolite of vitamin A1 (all-trans-retinol) that mediates the functions of vitamin A1 required for growth and development.
See Gastrulation and Retinoic acid
Rib cage
The rib cage or thoracic cage is an endoskeletal enclosure in the thorax of most vertebrates that comprises the ribs, vertebral column and sternum, which protect the vital organs of the thoracic cavity, such as the heart, lungs and great vessels and support the shoulder girdle to form the core part of the axial skeleton.
Sea urchin
Sea urchins or urchins, alternatively known as sea hedgehogs, are typically spiny, globular animals, echinoderms in the class Echinoidea. Gastrulation and sea urchin are animal developmental biology.
See Gastrulation and Sea urchin
Sea urchin skeletogenesis
Skeletogenesis is a key morphogenetic event in the embryonic development of vertebrates and is of equal, although transient, importance in the development of the sea urchin, a marine invertebrate. Gastrulation and sea urchin skeletogenesis are animal developmental biology.
See Gastrulation and Sea urchin skeletogenesis
SNAI1
Zinc finger protein SNAI1 (sometimes referred to as Snail) is a protein that in humans is encoded by the SNAI1 gene.
Spindle apparatus
In cell biology, the spindle apparatus is the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells.
See Gastrulation and Spindle apparatus
Sponge
Sponges (also known as sea sponges), the members of the phylum Porifera (meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts.
Symmetry in biology
Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria.
See Gastrulation and Symmetry in biology
T-box transcription factor T
T-box transcription factor T, also known as Brachyury protein, is encoded for in humans by the TBXT gene. Gastrulation and t-box transcription factor T are embryology.
See Gastrulation and T-box transcription factor T
Three Rs (animal research)
The Three Rs (3Rs) are guiding principles for more ethical use of animals in product testing and scientific research.
See Gastrulation and Three Rs (animal research)
Tissue (biology)
In biology, tissue is an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function.
See Gastrulation and Tissue (biology)
Transforming growth factor beta
Transforming growth factor beta (TGF-β) is a multifunctional cytokine belonging to the transforming growth factor superfamily that includes three different mammalian isoforms (TGF-β 1 to 3, HGNC symbols TGFB1, TGFB2, TGFB3) and many other signaling proteins.
See Gastrulation and Transforming growth factor beta
Triploblasty
Triploblasty is a condition of the gastrula in which there are three primary germ layers: the ectoderm, mesoderm, and endoderm. Gastrulation and Triploblasty are animal developmental biology.
See Gastrulation and Triploblasty
Vegetal rotation
Vegetal rotation is a morphogenetic movement that drives mesoderm internalization during gastrulation in amphibian embryos. Gastrulation and Vegetal rotation are embryology.
See Gastrulation and Vegetal rotation
Vertebra
Each vertebra (vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates.
Wnt signaling pathway
The Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors.
See Gastrulation and Wnt signaling pathway
Xenopus
Xenopus (Gk., ξενος, xenos.
References
[1] https://en.wikipedia.org/wiki/Gastrulation
Also known as Blastophore, Blastopore, Gastrula, Gastrulated, Midgastrula.
, Fibroblast growth factor, Fibroblast growth factor 8, Fibroblast growth factor receptor 1, Frog, Gastrointestinal tract, Gastruloid, Genus, Germ layer, Hans Spemann, Heart, Hilde Mangold, Homeobox, Hypoblast, Induced pluripotent stem cell, Ingression (biology), Invagination, Involution (medicine), Koller's sickle, Lefty (protein), Lewis Wolpert, Liver, Mechanisms of Development, Mesenchyme, Mesoderm, Messenger RNA, Microtubule, Model organism, Mollusca, Mothers against decapentaplegic homolog 2, Mothers against decapentaplegic homolog 3, Mothers against decapentaplegic homolog 4, Mouth, Muscle, Nature Reviews Molecular Cell Biology, Necessity and sufficiency, Nervous system, Neural crest, Neurulation, Nodal homolog, Nodal signaling pathway, Notch signaling pathway, Notochord, Organ (biology), Organogenesis, Organoid, Pancreas, Placenta, Polarity in embryogenesis, Primitive node, Primitive streak, Protostome, Respiratory system, Retinoic acid, Rib cage, Sea urchin, Sea urchin skeletogenesis, SNAI1, Spindle apparatus, Sponge, Symmetry in biology, T-box transcription factor T, Three Rs (animal research), Tissue (biology), Transforming growth factor beta, Triploblasty, Vegetal rotation, Vertebra, Wnt signaling pathway, Xenopus.