Histogenesis

Histogenesis is the formation of different tissues from undifferentiated cells.^[1] These cells are constituents of three primary germ layers, the endoderm, mesoderm, and ectoderm. The science of the microscopic structures of the tissues formed within histogenesis is termed histology.

A germ layer is a collection of cells, formed during animal and mammalian embryogenesis. Germ layers are typically pronounced within vertebrate organisms; however, animals or mammals more complex than sponges (eumetazoans and agnotozoans) produce two or three primary tissue layers. Animals with radial symmetry, such as cnidarians, produce two layers, called the ectoderm and endoderm. They are 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 or mammal's tissues and organs through a process called organogenesis.

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

• Histology
• List of human cell types derived from the germ layers

• Microsoft Corporation. Histogenesis Archived 2009-03-28 at the Wayback Machine (Archived 2009-10-31). Encarta World English Dictionary (North American Edition). URL accessed on 14 May 2005.
• Evers, Christine A., Lisa Starr. Biology:Concepts and Applications. 6th ed. United States:Thomson, 2006. ISBN 978-0-534-46224-6.