Editing Invagination (section)

{{Short description|Process in embryonic development}}
[[File:Tissue invagination.tif|thumb|358x358px|A sheet of cells undergoing invagination]]
'''Invagination''' is the process of a surface folding in on itself to form a cavity, pouch or tube. In [[developmental biology]], invagination of [[Epithelium|epithelial sheets]] occurs in many contexts during [[Animal embryonic development|embryonic development]]. Invagination is critical for making the [[Archenteron|primitive gut]] during [[gastrulation]] in many organisms, forming the [[neural tube]] in [[Vertebrate|vertebrates]], and in the [[morphogenesis]] of countless [[Organ (biology)|organs]] and sensory structures. Models of invagination that have been most thoroughly studied include the ventral furrow in [[Drosophila melanogaster|''Drosophila'' ''melanogaster'']], [[neural tube]] formation, and [[gastrulation]] in many marine organisms. The cellular mechanisms of invagination vary from one context to another but at their core they involve changing the mechanics of one side of a sheet of cells such that this pressure induces a bend in the tissue. 

The term, originally used in [[embryology]], has been adopted in other disciplines as well.