The infrequent bowel movements in young infants who are exclusively breast-fed

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 human microbiota begins developing at birth and undergoes continual change as we age. Infancy marks a critical period of microbial sensitivity, offering a “window of opportunity” during which beneficial microbes help mature the immune system. By age three, children typically develop a more stable and diverse microbial community. Newborns acquire microbes from their immediate environment; vaginal delivery favors maternal vaginal microbes, while cesarean births favor microbes from the skin...

DefinitionIrritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by recurrent combinations of abdominal pain, bloating, diarrhea, or constipation.Pathophysiology of irritable bowel syndromeIts pathophysiology is multifactorial, involving disturbances in motility, sensory processing, microbial balance, barrier integrity, and gut–brain communication. These mechanisms interact to produce symptoms that vary across IBS subtypes.Altered Motility PatternsDisordered...

Evaluating the rectum and anus plays a crucial role in conducting a thorough physical examination of the gastrointestinal system. Although it may be uncomfortable and often embarrassing for the patient, it holds immense diagnostic value, particularly in detecting gastrointestinal diseases and abnormalities. This guide will explain how to perform this assessment using inspection and palpation methods.
Rectal Inspection
Begin by inspecting the perianal and anal areas for color, texture, rashes,...

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 large intestine is where the final stages of digestion happen. When the cecum receives chyme, it contains undigested carbohydrates that undergo fermentation. Gut bacteria ferment these carbohydrates to produce short-chain fatty acids that provide some energy and help synthesize essential vitamins.
As the chyme moves to the colon, it triggers two characteristic sluggish contractions - haustral churning and mass peristalsis. Haustral churning involves the rhythmic contraction and relaxation...