invagação

Invaginação is a term used in biology and medicine to describe the process where a structure or tissue folds inward upon itself. This folding can occur in various contexts and at different scales. In cellular biology, invagination is a key mechanism for endocytosis, a process by which cells take in substances from their external environment. During endocytosis, the cell membrane indents and then pinches off to form a vesicle containing the ingested material.

In developmental biology, invagination is a crucial step in the formation of embryonic structures. For instance, the formation of the archenteron, the primitive gut, in many developing embryos involves the invagination of the blastula. This inward folding establishes the basic body plan and the foundation for internal organs.

Medically, invagination can refer to pathological conditions. Intussusception is a specific type of invagination where one segment of the intestine telescopes into an adjacent segment. This can obstruct the passage of food and blood flow, leading to serious complications. This condition most commonly affects infants and young children.

The process of invagination is driven by changes in cell shape and the mechanical forces generated by the cytoskeleton. It is a fundamental biological process essential for a wide range of cellular and developmental functions, as well as a potential cause of disease.