The digestive system includes the tube and sac-like structures that transport food through the body including the esophagus, stomach, small bowel, colon, rectum and anus. The liver and pancreas are also part of the digestive system, producing substances that aid in the breakdown and absorption of food. Abnormalities of the processes involved in the breakdown, absorption and transport of food lead to an array of digestive problems.
Secretory Deficiencies
Secretions produced by the pancreas aid in the digestion of fats, proteins and starch. A deficiency of pancreatic enzymes secreted into the small bowel leads to digestive problems. Merck Manuals Online Medical Library explains that people with chronic pancreatitis lose the capacity to produce digestive enzymes due to inflammation and scarring. Without sufficient digestive enzymes, increasing proportions of food pass through the bowels undigested. Weight loss, fatty stools, diarrhea, abdominal gas and bloating develop. People with cystic fibrosis frequently experience similar symptoms. With cystic fibrosis, abnormally thick secretions clog the pancreas, obstructing flow of the digestive juices. Backup of the digestive enzymes damages the pancreas, further decreasing production and secretion.
Malabsorption
Villi line the small bowel and absorb digested nutrients. Diseases that interfere with the structure or function of the villi impair absorption. The National Institute of Diabetes and Digestive and Kidney Diseases notes that people with celiac disease have an abnormal reaction to dietary gluten, leading to inflammation and destruction of the villi. Decreased food absorption results, causing digestive symptoms that may include abdominal pain, bloating, weight loss, fatty stools and diarrhea or constipation. Whipple's disease is another malabsorptive disorder caused by infection of the small bowel with the bacterium Tropheryma whipplei. The infection leads to thickening and distortion of the villi with decreased absorption of nutrients. Common symptoms include weight loss, abdominal pain, diarrhea and fever. The infection may spread to other parts of the body, causing additional symptoms.
Motility Disturbances
The esophagus, stomach and bowels have involuntary muscles that propel food and stool through the gastrointestinal system. Increased or decreased activity, or motility, can cause digestive problems. People with long-standing diabetes often develop nerve problems that cause decreased stomach motility, or gastroparesis. Food stays in the stomach for a prolonged period, causing heartburn, bloating, decreased appetite and weight loss. The National Institute of Diabetes and Digestive and Kidney Diseases notes that other possible causes of gastroparesis include bulimia, Parkinson's disease, amyloidosis, hypothyroidism, gastroesophageal reflux disease, sarcoidosis and certain medications. Irritable bowel syndrome, a functional disorder of the colon, can cause increased colon motility and diarrhea. Alternatively, decreased motility can lead to constipation. Other symptoms of irritable bowel syndrome include fecal urgency, abdominal cramps, bloating and frequent passage of gas.
References
- Merck Manuals: Chronic Pancreatitis
- National Heart, Lung and Blood Institute: Cystic Fibrosis
- National Institute of Diabetes and Digestive and Kidney Diseases: Celiac Disease
- National Institute of Diabetes and Digestive and Kidney Diseases: Whipple's Disease
- National Institute of Diabetes and Digestive and Kidney Diseases: Gastroparesis
