The mucosal barrier is a protective layer that lines various organs in the body, such as the gastrointestinal tract, respiratory system, and urogenital tract. It consists of mucus, epithelial cells, and immune cells, which work together to prevent harmful substances, pathogens, and toxins from entering the body. This barrier plays a crucial role in maintaining overall health and preventing infections. In the gastrointestinal tract, the mucosal barrier helps to protect the lining from digestive acids and enzymes while allowing the absorption of nutrients. Disruption of this barrier can lead to conditions like inflammatory bowel disease or gastritis, highlighting its importance in digestive health.