membranöse

Membranous is a term used across biology, anatomy, and medicine to describe structures that are related to membranes or that have a thin, sheet-like, membrane‑like quality. The word is often contrasted with non‑membranous components, which are not enclosed by a lipid bilayer.

In cell biology, membranes define boundaries and compartments within the cell. They regulate transport, signaling, and the composition of cellular spaces. Many important structures are membranous, including the plasma membrane, endoplasmic reticulum, Golgi apparatus, mitochondria, and the nuclear envelope. By contrast, some cellular components—such as ribosomes and cytoskeletal elements—are non‑membranous.

In development and anatomy, membranous describes processes and tissues formed or organized around membranes. A key example is intramembranous ossification, where certain bones (notably many of the skull bones) form directly from mesenchymal tissue without a cartilage stage. The term also appears in descriptions of mucous membranes, serous membranes, and other sheet‑like tissues.

In medicine, membranous is used to name conditions involving membranes. Membranous nephropathy (membranous glomerulopathy) is a kidney disease characterized by thickening of the glomerular basement membrane due to immune complex deposition. It can be primary or secondary to autoimmune diseases, infections, drugs, or malignancies.

In botany and materials science, membranous can describe leaves, seed coats, or thin, flexible tissue that functions like a membrane. Overall, membranous emphasizes a membrane‑related, sheet‑like, or enclosed quality across diverse disciplines. In Norwegian, membranøse is the equivalent adjective.