Morphogenesis

The generation of biological shape through processes including tissue growth, cell movement and changes in cellular organisation.

Formation of a tissue lumen through polarized membrane organization, transport and related cell behaviours. Hollowing and apoptotic cavitation are distinct possible mechanisms.

The arrangement and dimensions of cells, junctions and lumina in an epithelium. Shared polarity orientation alone does not fix whether the tissue is a sheet, cyst or elongated tube.

Unequal growth of coupled tissue regions or layers. Mechanical incompatibility can generate stress and deformation even when no localized external force is imposed.

The epithelial invagination that internalizes prospective mesoderm during early fly development. Pulsed apical contractility and tissue coupling contribute to the movement.

Reduction of a cell's apical surface area, often through localized actomyosin contractility. Coordinated constriction can bend an epithelial sheet when forces are transmitted through appropriate attachments.

Elongation of the early fly embryonic tissue through processes including polarized junction remodelling and cell intercalation. Neighbour changes and individual cell-shape changes make separable contributions to tissue deformation.

Formation of projecting myocardial structures on the luminal side of a ventricular wall. Differentiation, adhesion, rearrangement and proliferation can contribute, so absent trabeculae do not uniquely diagnose a division defect.

Creation and organization of an internal space in a tissue. Polarized surface delivery, division orientation, fluid transport and sometimes cell clearance can contribute; a cavity alone does not identify its mechanism.

An epithelial enclosure around a lumen, used experimentally to study coordinated polarity, division and surface traffic. Multiple lumina do not necessarily imply loss of polarity in every cell.

A transient region where apical determinants and membrane traffic organize a new luminal surface during epithelial polarization.

Development of a branched tissue network through coordinated cell proliferation, shape change, cell migration and rearrangement. A final tree does not uniquely identify which cellular process generated it.

Alteration of cellular geometry, which can contribute to tissue deformation without a change in cell number. Its contribution can be distinguished from neighbour exchange by following cell outlines over time.