Abstract
The gastrointestinal (GI) tract is a highly efficient organ system with specialized structures to facilitate digestion and absorption of nutrients to meet the body's needs. The presence of nutrients in the GI tract supports optimal structure and function, stimulates regulatory hormones, and supports the microbiota, the population of microorganisms residing in the GI tract. A lack of enteral nutrition (EN) results in impaired GI integrity and serious patient complications, making EN a priority. Normal GI physiology is reviewed, and the regulatory impact of luminal nutrients on GI function is discussed.