organogenesis

In animal development, organogenesis (organo-genesis, compound of the Greek words όργανον "that with which one works"^[1], and γένεσις "origin, creation, generation"^[2]) 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.

Production

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.

See also

• Ectoderm
• Embryogenesis
• Endoderm
• Eye development
• Germ layer
• Germ line development
• Heart development
• Histogenesis
• Limb development
• Mesoderm
• Morphogenesis

Notes

References

Look up organogenesis in Wiktionary, the free dictionary.

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