Structure and function

The gastrointestinal system comprises the hollow organs from mouth to anus that form the gastrointestinal tract, the pancreas, which mainly secretes digestive juices into the small intestine, and the liver and biliary system, which perform vital metabolic functions in addition to their contribution to digestion and absorption of nutrients. A hollow tubular structure into which nutrient-rich food is coerced, and from which wastes are expelled, is found in the most primitive multicellular...

Gastrooesophageal reflux and hiatus hernia

Acid in contact with squamous epithelium causes pain and heartburn and possibly damage (oesophagitis) Diaphragm contributes to sphincter function Axis of gastro-oesophegeal junction Lower oesophageal sphincter Axis of gastro-oesophegeal junction Lower oesophageal sphincter Reduced efficacy of sphincter (loss of angle, no diaphragmatic contraction) Reduced efficacy of sphincter (loss of angle, no diaphragmatic contraction) Columnar epithelium (gastric or intestinal type) Columnar epithelium...

Anal fissure

A split in the skin of the anal canal causes acute tearing pain, particularly on defecation. There may also be some bleeding. The cause is constipation and hard stool. On examination, there is a linear tear in the skin. Ninety percent of tears are posterior and 10 anterior. There may be a skin tag, called a sentinel pile, at the edge of a chronic tear. Stool softeners and alleviating constipation are the main treatments and, in the acute state, local application of glyceryl trinitrate ointment,...

Common disorders

Anorectal disorders typically cause pain, itching (pruritis ani) and bleeding (haematochesia). Pain can inhibit defecation, resulting in hardening of the stool and a self-perpetuating cycle of constipation. Inflammation causes diarrhoea and the passage of mucus. Chronic inflammation can reduce the ability of the rectum to dilate, causing urgency of defecation. Tenesmus is the sense of incomplete defecation. Incontinence is a distressing symptom, which may result from local disease, severe...

Starvation malnutrition and anorexia

Malnutrition has many causes, of which economic deprivation is the commonest. However, even in wealthy societies, ill health, gastrointestinal diseases, such as oesophageal cancer, and anorexia nervosa, as well as voluntary fasting, can all cause malnutrition and starvation. The BMI is abnormally low and other measures, such as skin-fold thickness and muscle strength and mass, are low. Listlessness and lethargy occur and with severe starvation, multiple organ failure may occur. In women,...

Carbohydrates

Blood glucose levels are maintained within tight limits. Glucose is 58 Integrated function essential for neuronal function and, if levels fall too low, hypogly-caemia causes neuroglycopenia, which can cause coma and death. On the other hand, sustained high blood glucose levels cause widespread damage to the body, particularly to blood vessels, as in diabetes mellitus. The liver plays a critical role in maintaining normal blood glucose levels. It is a major store of glucose, in the form of...

Peptic ulcer and Helicobacter pylori

' Up to 80 of population infected 1 15 get peptic ulcer 1 Others may develop - gastric lymphoma Most remain well Gastrectomy 1 Vagotomy J Antacids - ineffective H2 receptor antagonists n Proton pump inhibitors J Proton pump inhibitors + 2 antibiotics ' Up to 80 of population infected 1 15 get peptic ulcer 1 Others may develop - gastric lymphoma Most remain well Gastrectomy 1 Vagotomy J Antacids - ineffective H2 receptor antagonists n Proton pump inhibitors J Proton pump inhibitors + 2...