 Organs derived from each germ layer. Image from NCBI. A germ layer is a collection of cells, formed during animal embryogenesis. Germ layers are only really pronounced in the vertebrates. However, all animals more complex than sponges (eumetazoans and agnotozoans) produce two or three primary tissue layers (sometimes called primary germ layers). Animals with radial symmetry, like cnidarians, produce two called ectoderm and endoderm, making them diploblastic. Animals with bilateral symmetry produce a third layer in-between called mesoderm, making them triploblastic. Germ layers will eventually give rise to all of an animal’s tissues and organs through a process called organogenesis. Image File history File links Cell_differentiation. ...
Image File history File links Cell_differentiation. ...
Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell. Cells in culture, stained for keratin (red) and DNA (green). ...
Embryogenesis is the process by which the embryo is formed and develops. ...
Classes and Clades See below Male and female Superb Fairy-wren Vertebrates are members of the subphylum Vertebrata (within the phylum Chordata), specifically, those chordates with backbones or spinal columns. ...
Animalia redirects here. ...
Classes Calcarea Hexactinellida Demospongiae The sponges or poriferans (from Latin porus pore and ferre to bear) are animals of the phylum Porifera. ...
subgroups Ctenophora Cnidaria Bilateria Eumetazoa is a clade comprising all major animal groups except sponges. ...
The elaborate patterns on the wings of butterflies are one example of biological symmetry. ...
Classes Anthozoa - Corals and sea anemones Scyphozoa - Jellyfish Staurozoa - Stalked jellyfish Cubozoa - Sea wasps or box jellyfish Polypodiozoa Hydrozoa - Hydroids, hydra-like animals Cnidaria[1] (IPA: [2]) is a phylum containing some 11,000 species of relatively simple animals found exclusively in aquatic, mostly marine, environments. ...
The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
Diploblastic is a condition of the ovum in which there are two primary germinal layers: the ectoderm and endoderm. ...
The elaborate patterns on the wings of butterflies are one example of biological symmetry. ...
The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
Triploblastic is a condition of the ovum in which there are three primary germinal layers: the ectoderm, mesoderm, and endoderm. ...
Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ...
In biology, an organ (Latin: organum, instrument, tool) is a group of tissues that perform a specific function or group of functions. ...
Organogenesis is a stage of animal development where the ectoderm, endoderm, and mesoderm are formed. ...
Germ layers
 Gastrulation of a diploblast: The formation of germ layers from a (1) blastula to a (2) gastrula. Some of the ectoderm cells (orange) move inward forming the endoderm (red). Caspar Friedrich Wolff observed organization of the early embryo in leaf-like layers. Later, Heinz Christian Pander discovered germ layers while studying chick embryos. Download high resolution version (801x486, 94 KB) Author Pidalka44. ...
Download high resolution version (801x486, 94 KB) Author Pidalka44. ...
Caspar Friedrich Wolff (January 18, 1734 _ February 22, 1794) was a significant German anatomist. ...
Pander studied the chick embryo and discovered the germ layers (i. ...
Among animals, sponges show the simplest organization, having a single germ layer. Although they have differentiated cells (e.g. collar cells), they lack true tissue coordination. Diploblastic animals, Cnidaria and ctenophores, show an increase in complexity, having two germ layers, the endoderm and ectoderm. Diploblastic animals are organized into recognisable tissues. All higher animals (from flatworms to man) are triploblastic, having in addition a mesoderm. Triploblastic animals develop recognisable organs. Animalia redirects here. ...
Classes Calcarea Hexactinellida Demospongiae The sponges or poriferans (from Latin porus pore and ferre to bear) are animals of the phylum Porifera. ...
Choanocytes (also known as collar cells) are cells that line the interior body walls of sponges that contain a central flagellum surrounded by a collar of microvilli. ...
Diploblastic is a condition of the ovum in which there are two primary germinal layers: the ectoderm and endoderm. ...
Classes Anthozoa - Corals and sea anemones Scyphozoa - Jellyfish Staurozoa - Stalked jellyfish Cubozoa - Sea wasps or box jellyfish Polypodiozoa Hydrozoa - Hydroids, hydra-like animals Cnidaria[1] (IPA: [2]) is a phylum containing some 11,000 species of relatively simple animals found exclusively in aquatic, mostly marine, environments. ...
Classes Tentaculata Nuda Ctenophores are jellyfish-like animals commonly called comb jellies, sea gooseberries, sea walnuts, or Venus girdles. ...
The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
Triploblastic is a condition of the ovum in which there are three primary germinal layers: the ectoderm, mesoderm, and endoderm. ...
The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
Development Fertilization leads to the formation of a zygote. During the next stage, cleavage, mitotic cell divisions transform the zygote into a tiny ball of cells called a blastula. This early embryonic form undergoes a massive reorganization called gastrulation forming a gastrula with either two or three layers (the germ layers). In all vertebrates, these are the forerunners of all adult tissues and organs. Fertilisation or fertilization (also known as conception, fecundation and syngamy), is fusion of gametes to form a new organism of the same species. ...
A zygote (Greek: ζυγωτόν) is a cell that is the result of fertilization. ...
In embryology, cleavage is the division of cells in the early embryo. ...
Mitosis divides genetic information during cell division. ...
Blastulation. ...
1 - blastula, 2 - gastrula; orange - ectoderm, red - endoderm. ...
1 - blastula, 2 - gastrula; orange - ectoderm, red - endoderm. ...
Classes and Clades See below Male and female Superb Fairy-wren Vertebrates are members of the subphylum Vertebrata (within the phylum Chordata), specifically, those chordates with backbones or spinal columns. ...
The appearance of the archenteron marks the onset of gastrulation. The archenteron is an indentation that forms early on in a developing blastula. ...
Endoderm -
The endoderm is one of the germ layers formed during animal embryogenesis. Cells migrating inward along the archenteron form the inner layer of the gastrula, which develops into the endoderm. Image File history File links Endoderm2. ...
Image File history File links Endoderm2. ...
The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
Respiratory system The lungs flank the heart and great vessels in the chest cavity. ...
The pancreas is an organ in the digestive and endocrine system (of vertebrates[2]). It is both exocrine (secreting pancreatic juice containing digestive enzymes) and endocrine (producing several important hormones, including insulin, glucagon, and somatostatin). ...
The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
The endoderm consists at first of flattened cells, which subsequently become columnar. It forms the epithelial lining of the whole of the digestive tube excepting part of the mouth and pharynx and the terminal part of the rectum (which are lined by involutions of the ectoderm). The lining cells of all the glands which open into the digestive tube, including those of the liver and pancreas, the epithelium of the auditory tube and tympanic cavity, of the trachea, bronchi, and air cells of the lungs, of the urinary bladder and part of the urethra, and that which lines the follicles of the thyroid gland and thymus are also formed by this layer.
The endoderm forms: stomach, colon, liver, pancreas, urinary bladder; epithelial parts of trachea, lungs, pharynx, thyroid, intestine. The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
Mesoderm -
The mesoderm germ layer forms in the embryos of animals more complex than cnidarians, making them triploblastic. During gastrulation, some of the cells migrating inward contribute to the mesoderm, an additional layer between the endoderm and the ectoderm. Image File history File links Mesoderm. ...
Image File history File links Mesoderm. ...
The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
Cardiac muscle is a type of involuntary mononucleated, or uninucleated, striated muscle found exclusively within the heart. ...
A top-down view of skeletal muscle Skeletal muscle is a type of striated muscle, attached to the skeleton. ...
Cultured Smooth muscle of the aorta. ...
It has been suggested that Renal anomalies and Renal plasma threshold be merged into this article or section. ...
Human red blood cells Red blood cells are the most common type of blood cell and the vertebrate bodys principal means of delivering oxygen from the lungs or gills to body tissues via the blood. ...
The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
It has been suggested that embryology be merged into this article or section. ...
Animalia redirects here. ...
Classes Anthozoa - Corals and sea anemones Scyphozoa - Jellyfish Staurozoa - Stalked jellyfish Cubozoa - Sea wasps or box jellyfish Polypodiozoa Hydrozoa - Hydroids, hydra-like animals Cnidaria[1] (IPA: [2]) is a phylum containing some 11,000 species of relatively simple animals found exclusively in aquatic, mostly marine, environments. ...
Triploblastic is a condition of the ovum in which there are three primary germinal layers: the ectoderm, mesoderm, and endoderm. ...
1 - blastula, 2 - gastrula; orange - ectoderm, red - endoderm. ...
The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
This key innovation evolved hundreds of millions of years ago and led to the evolution of nearly all large, complex animals. The formation of a mesoderm led to the formation of a coelom. Organs formed inside a coelom can freely move, grow, and develop independently of the body wall while fluid cushions and protects them from shocks. By the broadest definition, a body cavity is any fluid filled space in a multicellular organism. ...
The mesoderm forms: skeletal muscle, skeleton, dermis of skin, connective tissue, urogenital system, heart, blood (lymph cells), and spleen. The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
Ectoderm -
The ectoderm is the start of a tissue that covers the body surfaces. It emerges first and forms from the outermost of the germ layers. Image File history File links Ectoderm. ...
Image File history File links Ectoderm. ...
The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
It has been suggested that this article or section be merged with skin. ...
Drawing by Santiago Ramón y Cajal of neurons in the pigeon cerebellum. ...
Melanocytes are cells located in the bottom layer of the skins epidermis. ...
The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
The ectoderm forms: Central nervous system, retina and lens, cranial and sensory, ganglia and nerves, pigment cells, head connective tissue, epidermis, hair, mammary glands. The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
Neural crest Due to the great importance of the neural crest it has been referred to as the fourth germ layer. The neural crest, a component of the ectoderm, is one of several ridgelike clusters of cells found on either side of the neural tube in vertebrate embryos. ...
References - Evers, Christine A., Lisa Starr. Biology:Concepts and Applications. 6th ed. United States:Thomson, 2006. ISBN 0-534-46224-3.
See also | v • d • e Mammalian development of embryo and development of fetus (some dates are approximate - see Carnegie stages) | | Week 1: Zygote - Morula - Blastula/Blastomere/Blastosphere - Archenteron/Primitive streak - Blastopore - Allantois - Trophoblast (Cytotrophoblast - Syncytiotrophoblast - Gestational sac) Week 2: Yolk sac - Vitelline duct - Bilaminar disc Embryonic stem cells differentiate into cells in various body organs. ...
Embryogenesis is the process by which the embryo is formed and develops. ...
An Introduction to Histogenesis Histogenesis is defined as the formation of tissues and organs from undifferentiated cells (Encarta Dictionary). ...
Neurulation is a part of organogenesis in vertebrate embryos. ...
Organogenesis is a stage of animal development where the ectoderm, endoderm, and mesoderm are formed. ...
Mammalian embryogenesis is the process of cell division and cellular differentiation which leads to the development of a mammalian embryo. ...
This article or section is in need of attention from an expert on the subject. ...
It has been suggested that embryology be merged into this article or section. ...
Fetal (U.S. English; Foetal UK English) development is the process in which a fetus (U.S. English; Foetus UK English) develops during gestation, from the times of conception until birth. ...
Human fetus at eight weeks. ...
In embryology, Carnegie stages are a standardized system of 23 stages used to provide a unified developmental chronology of the embryo. ...
A zygote (Greek: ζυγωτόν) is a cell that is the result of fertilization. ...
Morula is a stage of embryonic development in animals, including the 16-cell phase, the 32-cell phase, and the 64-cell phase. ...
Blastulation. ...
A blastomere is the structure which results from the divisions of a fertilised egg during embryonic development . ...
Blastulation. ...
The archenteron is an indentation that forms early on in a developing blastula. ...
The primitive streak is a structure that forms during the early stages of avian, reptilian and mammalian embryonic development. ...
A blastopore is an opening into the archenteron during the embryonic stages of an organism. ...
Allantois is a part of a developing animal embryo. ...
The trophoblast (from Greek threphein: to feed) is considered to be the first of all embryonic annexes. ...
The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...
Syncytiotrophoblasts are cells found in the placenta of human embryos. ...
The gestational sac is the only available intrauterine structure that can be used to determine if an intrauterine pregnancy (IUP) exists, until the embryo is identified. ...
The yolk sac is the first element seen in the gestational sac during pregnancy, usually at 5 weeks gestation. ...
At the end of the fourth week the yolk-sac presents the appearance of a small pear-shaped vesicle (umbilical vesicle) opening into the digestive tube by a long narrow tube, the vitelline duct. ...
This article, image, template or category should belong in one or more categories. ...
Week 3: Hensen's node - Gastrula/Gastrulation - Trilaminar embryo Branchial arch (1st) - Branchial pouch - Meckel's cartilage - Somite/Somitomere - Sclerotome - Myotome - Germ layer (Ectoderm, Endoderm, Mesoderm, Chordamesoderm, Paraxial mesoderm, Intermediate mesoderm, Lateral plate mesoderm, Splanchnopleure, Somatopleure) Hensens Node is the organizer for gastrulation in birds. ...
1 - blastula, 2 - gastrula; orange - ectoderm, red - endoderm. ...
1 - blastula, 2 - gastrula; orange - ectoderm, red - endoderm. ...
It has been suggested that this article or section be merged with Embryogenesis. ...
In the development of vertebrate animals, the branchial arches (or pharyngeal arches) develop during the fourth and fifth week in utero as a series of mesodermal outpouchings on the left and right sides of the developing pharynx. ...
It has been suggested that this article or section be merged into branchial arch. ...
Pharyngeal or branchial pouches form on the endodermal side between the branchial arches, and pharyngeal grooves (or clefts) form from the lateral ectodermal surface of the neck region to separate the arches. ...
The cartilaginous bar of the mandibular arch is formed by what are known as Meckel’s cartilages (right and left) ; above this the incus is developed. ...
In the developing vertebrate embryo, somites are masses of mesoderm distributed along the two sides of the neural tube and that will eventually become dermis (dermatome), skeletal muscle (myotome), and vertebrae (sclerotome). ...
In the developing vertebrate embryo, the somitomeres are loose masses of paraxial mesoderm derived cells that form along each side of the neural tube towards the end of the third gestational week. ...
In vertebrate embryonic development, a group of embryonic tissues formed from somites that develop into the vertebrae. ...
In vertebrate embryonic development, a group of tissues formed from somites that develop into the body wall muscle. ...
The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
Chordamesoderm is a type of mesoderm that lies along the central axis, under the neural tube. ...
Paraxial mesoderm is the area of mesoderm that forms just lateral to the neural tube on both sides. ...
Intermediate mesoderm is a type of mesoderm that is located between the paraxial mesoderm and the lateral plate. ...
Lateral plate mesoderm (or hypomere) is a type of mesoderm that is found at the periphery of the embryo. ...
In the anatomy of an embryo, the splanchnopleure is a structure created during embryogenesis when the lateral mesoderm splits into two layers. ...
When the lateral mesoderm splits into two layers, the outer (or somatic) one becomes applied to the inner surface of the ectoderm, and with it forms the somatopleure. ...
Histogenesis and Organogenesis An Introduction to Histogenesis Histogenesis is defined as the formation of tissues and organs from undifferentiated cells (Encarta Dictionary). ...
Organogenesis is a stage of animal development where the ectoderm, endoderm, and mesoderm are formed. ...
Glands: Thyroglossal duct A gland is an organ in an animals body that synthesizes a substance for release such as hormones, often into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). ...
The thyroglossal duct is an embryological anatomical structure which forms the connection between the initial area of development of the thyroid gland and its final position. ...
Uterine support: Placenta - Umbilical cord (Umbilical artery, Umbilical vein, Wharton's jelly) - Amniotic sac (Amnion, Chorion) The uterus or womb is the major female reproductive organ of most mammals, including humans. ...
The placenta is an ephemeral (temporary) organ present in female placental vertebrates during gestation (pregnancy), but a placenta has evolved independently also in other animals as well, for instance scorpions and velvet worms. ...
In placental mammals, the umbilical cord is a tube that connects a developing embryo or fetus to its placenta. ...
Umbilical arteries carry deoxygenated blood from the fetus to the placenta in the umbilical cord. ...
Fetal circulation; the umbilical vein is the large, red vessel at the far left The umbilical vein is a blood vessel present during fetal development that carries oxygenated blood from the placenta to the growing fetus. ...
Whartons jelly is a gelatinous substance within the umbilical cord. ...
A drawing of the amniotic sac from Grays Anatomy. ...
For the alien race in Stephen Donaldsons The Gap Cycle, see Amnion (Gap Cycle). ...
For the entertainment company see Chorion (company) The chorion surrounds the embryo and other membranes. ...
Limb development: Limb bud - Apical Ectodermal Ridge/AER The vertebrate limb arises out of a general morphogenetic area called a limb field. ...
In embryology, the limb bud is a structure formed by the developing limb, derived from lateral plate mesoderm[citation needed]. It is intimately related with the apical ectodermal ridge, which secretes factors inducing the initial differentiation of the limb bud. ...
There are very few or no other articles that link to this one. ...
| Germ Layers: Ectoderm - Endoderm - Mesoderm The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ...
The endoderm, sometimes refered to as entoderm, is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. ...
The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ...
Production: Histogenesis - Organogenesis An Introduction to Histogenesis Histogenesis is defined as the formation of tissues and organs from undifferentiated cells (Encarta Dictionary). ...
Organogenesis is a stage of animal development where the ectoderm, endoderm, and mesoderm are formed. ...
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