Invaginering

Invaginering, or invagination, is the inward folding of a sheet of cells or tissue to form a pocket, cavity, or tube. It is a fundamental morphogenetic mechanism in many organisms and contexts.

In embryology, invagination contributes to gastrulation, as cells move inward to form the archenteron and establish the germ layers. It also participates in organ formation and can be involved in neurulation. In cell biology, membrane invagination is a key step in endocytosis, allowing the cell to internalize extracellular material by forming vesicles.

In medicine, invagination is associated with intussusception, a condition in which a segment of intestine telescopes into an adjacent segment, leading to obstruction. It occurs mainly in children but also in adults. Diagnosis and treatment depend on severity and may include non-surgical reduction or surgery.