<unk>  is full-thickness injury of the bowel wall.<unk>  of the gastrointestinal tract can be due to many causes but main causes are instrumentation during surgery or bowel obstruction. Spontaneous<unk>  can be caused by inflammation, connective tissue disorders, and medications. Terminal ileum is the commonest site for spontaneous<unk>  and may be the jejunum and colon. In neonatal<unk> , the terminal ileum and colon are the commonest sites for<unk> . The pathogenesis of NEC remains unknown but there are many factors for infection such as: Ninety percent of NEC cases occur in preterm infants due to immaturity of the gastrointestinal tract. Preterm infants have lower concentrations or more immature function of contributing mucosal defense factors than do term infants and adults. Regarding anatomy of GIT, the esophagus travels 3 regions of the body: the neck, thorax, and abdomen. Accordingly, it is divided into 3 parts: cervical, thoracic, and abdominal. The gastrointestinal tract has a form of general histology with some differences that reflect the specialization in functional anatomy. The GI tract can be divided into four concentric layers in the following order: Mucosa, Submucosa, muscular layer, and Adventitia or serosa.<unk>  of the gastrointestinal tract can be due to many causes but main causes are instrumentation during surgery or bowel obstruction. Spontaneous<unk>  can be caused by inflammation, connective tissue disorders, and medications. With bowel obstruction,<unk>  occurs proximal to the obstruction as pressure builds up within the bowel, exceeding intestinal perfusion pressure, and leading to ischemia and subsequently necrosis. Acute colonic pseudo-obstruction is an acute dilatation of the colon without mechanical obstruction of the flow of intestinal contents. The mechanism of<unk>  in patients with acute colonic pseudo-obstruction is unknown. Spinal anesthesia and pharmacologic agents are suggested to be the causes due to impairment of autonomic system.
Gastrointestinal perforation pathophysiology
Spontaneous bacterial peritonitis pathophysiology
Mesenteric ischemia pathophysiology
Secondary peritonitis pathophysiology
Diverticulitis pathophysiology
Upper gastrointestinal bleeding pathophysiology
Acute mesenteric ischemia pathophysiology
Ileus pathophysiology