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In animal development, organogenesis is the process by which the ectoderm, endoderm, and mesoderm develop into the internal organs of the organism. Internal organs initiate development in humans within the 3rd to 8th weeks in utero.The germ layers in organogenesis differ by three processes: folds, splits, and condensation. Developing early during this stage in chordate animals are the neural tube and notochord. Vertebrate animals all differentiate from the gastrula the same way. Vertebrates develop a neural crest that differentiates into many structures, including some bones, muscles, and components of the peripheral nervous system. The coelom of the body forms from a split of the mesoderm along the somite axis.


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The endoderm produces tissue within the lungs, thyroid, and pancreas. The mesoderm aids in the production of cardiac muscle, skeletal muscle, smooth muscle, tissues within the kidneys, and red blood cells. The ectoderm produces tissues within the epidermis and aids in the formation of neurons within the brain, and melanocytes.
Organs derived from each germ layer. Image from NCBI.

The proceeding graph represents the products produced by the three germ layers.

Germ Layer Category Product
Endoderm General[1] Gastrointestinal tract
Endodern General Respiratory tract
Endoderm General Endocrine glands and organs (liver and pancreas)
Mesoderm General Bones
Mesoderm General Most of the Circulatory system
Mesoderm General Connective tissues of the gut and integuments
Mesoderm General Excretory Tract
Mesoderm General Mesenchyme
Mesoderm General Mesothelium
Mesoderm General Muscles
Mesoderm General Peritoneum
Mesoderm General Reproductive System
Mesoderm General Urinary System
Mesoderm Vertebrate[2] Chordamesoderm
Mesoderm Vertebrate Paraxial mesoderm
Mesoderm Vertebrate Intermediate mesoderm
Mesoderm Vertebrate Lateral plate mesoderm
Ectoderm General Nervous system
Ectoderm General Outer part of integument
Ectoderm Vertebrate Skin (along with glands, hair, nails)
Ectoderm Vertebrate Epithelium of the mouth and nasal cavity
Ectoderm Vertebrate Lens and cornea of the eye
Ectoderm Vertebrate Melanocytes
Ectoderm Vertebrate Peripheral nervous system
Ectoderm Vertebrate Facial cartilage
Ectoderm Vertebrate Dentin (in teeth)
Ectoderm Vertebrate Brain (rhombencephalon, mesencephalon and prosencephalon)
Ectoderm Vertebrate Spinal cord and motor neurons
Ectoderm Vertebrate Retina
Ectoderm Vertebrate Posterior pituitary

See also


  1. The General category denotes that all or most of the animals containing this layer produce the adjacent product.
  2. The Vertebrate category denotes that all or most of the vertebrates containing this layer produce the adjacent product.


  • Evers, Christine A., Lisa Starr. Biology:Concepts and Applications. 6th ed. United States:Thomson, 2006. ISBN 0-534-46224-3.

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