Which epithelial structures are affected by inflammation leading to increased permeability?

Increased permeability in epithelial tissues during inflammation is primarily associated with tight junctions. Tight junctions are specialized structures that form a seal between epithelial cells, regulating the paracellular transport of molecules and maintaining the integrity of the epithelial barrier. They are essential for controlling the diffusion of ions, solutes, and water between the internal and external environments of tissues.

During inflammation, various mediators such as histamines and cytokines can disrupt the organization and function of tight junctions. This disruption causes the tight junctions to become less effective at forming barriers, leading to increased permeability. As a result, fluids, proteins, and leukocytes can more easily pass between epithelial cells, contributing to the characteristic signs of inflammation, such as swelling and redness.

Other structures like desmosomes and adherens junctions play a role in cell adhesion and maintaining tissue integrity but are not primarily responsible for permeability regulation. The basement membrane, while important for overall tissue support and filtration, does not directly govern the dynamic permeability changes seen during inflammatory processes. Therefore, the identification of tight junctions as the structures affected by inflammation due to their role in controlling epithelial permeability is crucial for understanding inflammatory responses at the cellular level.