Chapter 43: Gastrointestinal System Assessment

The gastrointestinal tract consists of four distinct tissue layers regulated by both autonomic and enteric nervous systems, extending from oral cavity to rectum with specialized accessory organs including hepatic, biliary, and pancreatic structures. Key physiological processes include hypothalamic regulation of food intake through ghrelin and leptin signaling, mechanical and chemical digestion beginning with mastication and salivation, esophageal peristalsis controlled by the lower esophageal sphincter, gastric acid secretion and protein breakdown, and nutrient absorption through intestinal villi and microvilli in the small bowel. The liver performs critical metabolic functions including bile synthesis, bilirubin conjugation, and detoxification through Kupffer cell filtration, while the gallbladder responds to cholecystokinin for bile release and the pancreas provides both digestive enzymes and endocrine hormones. Age-related physiological changes significantly impact gastrointestinal function through reduced gastric acid production, intrinsic factor deficiency, delayed motility, hepatic metabolism alterations, and increased susceptibility to biliary disorders. Comprehensive nursing assessment incorporates systematic collection of subjective data regarding symptom patterns including dysphagia, hematemesis, melena, and elimination changes, alongside medication history focusing on hepatotoxic agents and gastrointestinal irritants. Physical examination techniques follow a structured approach utilizing inspection of oral structures and abdominal contour, auscultation of bowel sounds, percussion for organ enlargement and fluid accumulation, and palpation for masses, tenderness, or hepatosplenomegaly, with digital rectal examination when clinically indicated for comprehensive evaluation.