Tight junctions form a continuous seal between adjacent epithelial cells, preventing the passage of molecules and ions through the space between cells (the paracellular pathway). This barrier function is crucial to maintain distinct compartments in tissues, control selective permeability, and protect underlying tissues from harmful substances. In surgical contexts, preserving tight junction integrity ensures effective barrier function in organs such as the intestines and kidneys, reducing the risk of infection and inflammation. Disruption of tight junctions can lead to increased permeability and contribute to pathological conditions like edema and organ dysfunction.

Reference: Robbins Basic Pathology, Kumar et al., 10th Edition.