This lesson explores three gastrointestinal imaging techniques: radionuclide testing, colonic transit studies, and virtual colonoscopy.
Radionuclide Testing
Radionuclide testing is a sophisticated medical technique for assessing gastrointestinal motility. It focuses on gastric emptying and colonic transit time. Radioactive markers track the movement of food through the digestive system, providing insights into gastrointestinal disorders.
In gastric emptying studies, a meal's liquid and...

Pharmacological therapies for IBS-C are designed to alleviate abdominal discomfort and enhance bowel function. In patients with IBS-C, fiber supplements may help soften stools and decrease straining, but may also lead to increased gas production and bloating. Osmotic laxatives like milk of magnesia are frequently used to soften stools and increase stool frequency in IBS-C patients. In addition, two drugs approved for use in severe IBS-C adult cases are linaclotide (Linzess) and lubiprostone...

Irritable Bowel Syndrome (IBS) is characterized by functional disturbances in the gastrointestinal system, presenting a cluster of symptoms without evident structural or biochemical abnormalities. It primarily affects the large intestine and may cause abdominal pain, bloating, excessive gas, diarrhea, constipation, or both.
IBS is a chronic condition that can persist over a long period or recur frequently.
The pathogenesis of IBS involves a complex interplay of the following factors:
Altered...

The human body contains a monogastric digestive system. In a monogastric digestive system, the stomach only contains one chamber in which it digests food. Several other animal species also have monogastric digestive systems, including pigs, horses, dogs, and birds. This chapter, however, focuses on the human digestive system.

Laxatives are primarily used to alleviate constipation, a common gastrointestinal disorder characterized by infrequent bowel movements and difficulty passing stools. They work by various mechanisms to increase the volume or frequency of bowel movements. The primary modes of action of laxatives include increasing stool bulk, softening the stool, stimulating intestinal motility, and osmotically drawing water into the intestines.
Osmotic or saline laxatives, like magnesium hydroxide or milk of...

Laxatives enhance bowel movements and alleviate constipation. They augment the stool's bulk, stimulate intestinal muscle contractions, draw water into the intestines, or soften the stool. There are five key types of laxatives: bulk laxatives, stimulant laxatives, osmotic laxatives, stool softeners, and lubricant laxatives.
Bulk-forming laxatives, such as psyllium, methylcellulose, and polycarbophil, absorb water in the intestine, increasing stool bulk and promoting bowel movement. This...