Organogenesis

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.

Production

File:Germ layers.png

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	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	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

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

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.

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