[First intestinal transit bipartition at the Mexican Institute for Social Security]

Intestinal obstruction triggers a series of physiological responses, starting with gas and fluid accumulation in the bowel segment proximal to the obstruction, leading to distension. This distended intestine compresses the diaphragm, hindering lung expansion and potentially leading to reduced respiratory effort, atelectasis, and pneumonia.To overcome the blockage, the gut intensifies contractions, causing colicky abdominal pain, nausea, and vomiting, which reduces fluid and food intake and...

Intestinal obstruction is a partial or complete blockage of the small or large intestine that disrupts the normal flow of intestinal contents through the lumen. This interruption impairs digestion, absorption, and fluid balance, and may lead to serious complications if not treated promptly.Mechanical ObstructionMechanical obstruction occurs when a physical blockage prevents intestinal contents from passing, arising from within the lumen or the bowel wall, or from external compression.Adhesions,...

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 solid...

Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, and electrolytes from food and drink also occurs in the intestine. The intestines can be divided into two structurally distinct organs—the small and large intestines.
Small Intestines
The small intestine is an ~7 meter-long tube with an inner diameter of just 2.5 cm. Since most nutrients are absorbed here, the inner lining of the small...

The intestinal phase of digestion is the third and final stage of the digestive process, occurring after the cephalic and gastric phases. It begins when chyme, a partially digested mixture of food and digestive enzymes, enters the small intestine from the stomach. This phase is crucial for nutrient absorption and involves complex hormonal and enzymatic interactions.
The arrival of the chyme in the small intestine distends the duodenum, which triggers the enterogastric reflex. This distension...

Gastrointestinal or GI motility disorders are characterized by irregular gastrointestinal tract movements, disrupting food transit from the mouth to the anus. They are caused by damage or dysfunction in gut muscles or nerves. These disorders can cause symptoms such as severe constipation, diarrhea, abdominal pain, and swallowing difficulties. Disorders can affect any segment of the GI tract and range widely in severity, from common conditions like GERD to life-threatening conditions like...