The gastrointestinal tract is protected by the barrier, comprising secretory, physical, and immune components.

The secretory barrier comprises the mucus and defense proteins, aiding in gut health maintenance.

The physical barrier is maintained by tight junctions between epithelial cells, preventing the entry of harmful substances.

The immune barrier involves immune cells and antimicrobial peptides, protecting against pathogens.

The gastrointestinal system is regulated by the enteric nervous system, or ENS, a division of the autonomic nervous system.

The ENS includes two plexuses: the myenteric, or Auerbach plexus, and the submucosal, or Meissner plexus.

The myenteric plexus, located between the gut muscle layers, regulates gut motility.

The submucosal plexus, found in the submucosa, controls secretions and blood flow within the gastrointestinal tract.