zonula Definition

A zonula, in the context of anatomy and cell biology, refers to a band of dense material that forms part of the cell-cell junctions, specifically the tight junctions (zonula occludens) and adherens junctions (zonula adherens). These junctions play crucial roles in maintaining the integrity of tissues and organs by regulating the permeability of the barrier between cells and the adhesion of adjacent cells. In architecture, a zonula can also refer to a decorative moulding or a strip.