Digestive System

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Gastrointestinal tract
This article uses anatomical terminology; for an overview, see Anatomical terminology. Cells in epithelial tumors often retain their basic epithelial character, remaining attached to one another and differentiating to form layered structures. Tight occluding junctions block diffusion; they typically form a seal or gasket around the apical end of cells comprising simple epithelia i. In addition to the alimentary canal, there are several important accessory organs that help your body to digest food Continue Scrolling To Read More Below It can provide a visual diagnosis e.

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Absorption Disorders Overview, Types

Intestinal gas consists principally of swallowed air and partly of by-products of digestion. When a person is in an upright position, gas diffuses to the uppermost portions of the colon. There it is compressed by the contraction of adjacent segments, giving rise to pain that…. Under normal atmospheric conditions, intestinal discomfort can be felt when air or gas collects in the intestines. Relief is obtained by expelling the gas…. Stomach , saclike expansion of the digestive system, between the esophagus and the small intestine; it is located in the anterior portion of the abdominal cavity in most vertebrates.

The stomach serves as a temporary receptacle for storage and mechanical distribution of food before it is passed into the intestine. Small intestine , a long, narrow, folded or coiled tube extending from the stomach to the large intestine; it is the region where most digestion and absorption of food takes place. It is about 6.

More About Intestinal gas 3 references found in Britannica articles Assorted References major reference In human digestive system: Intestinal gas cause of pain In digestive system disease: Intestinal gas role in intestinal squeeze In intestinal squeeze. Help us improve this article! Contact our editors with your feedback. You may find it helpful to search within the site to see how similar or related subjects are covered.

Any text you add should be original, not copied from other sources. At the bottom of the article, feel free to list any sources that support your changes, so that we can fully understand their context. Internet URLs are the best. Cells in epithelial tumors often retain their basic epithelial character, remaining attached to one another and differentiating to form layered structures. As long as the neoplastic cells respect the basement membrane, the tumor will remain localized.

But once cells break through this boundary they can enter circulation and metastasize. The name carcinoma is applied to any cancer malignant neoplasm of epithelial origin; adenocarcinoma names a cancer of glandular origin.

Cancers of mesenchymal origin are called sarcomas. How to use this resource. Epithelial tissue comprises an uninterrupted layer of cells. Epithelium covers nearly all external and internal body surfaces. Epithelial cells are attached to one another.

Special devices intercellular junctions, tonofilaments provide for structural integrity of the epithelium. There are several types of cell junctions. Keratinocytes are joined to one another by many adhering junctions. Tight occluding junctions block diffusion; they typically form a seal or gasket around the apical end of cells comprising simple epithelia i. This junction helps assure adequate separation between different fluid compartments i. Gap junctions provide direct intercytoplasmic communication between joined cells.

That is, ions or small molecules can pass through gap junctions directly from the cytoplasm of one cell into the cytoplasm of an adjacent cell, without passing into intercellular space. Intercellular spaces in epithelium are small. Within the epithelium, the narrow spaces between cells are sealed off from the external environment by cell junctions near the free surface of the cells.

Compared to ordinary connective tissue, epithelial tissue has very little interstitial fluid. Epithelial tissue is polarized. An epithelium has a free surface, the apical surface , exposed to the outside, and an attached surface, the basal surface , resting on the underlying connective tissue. In a simple single-layered epithelium, each cell is polarized. The base of each cell is attached to an underlying basement membrane while the apical end faces free space.

Lateral surfaces are attached to neighboring epithelial cells. Polarization of epithelial cell structure is particularly evident in secretory and absorptive cells where the arrangement of intracellular organelles reflects the directional transport of material.

Less visible but equally important is the localization of membrane proteins, which confer special properties to the membrane i. Epithelial cells are separated from the underlying tissue by a basement membrane.

The basement membrane is a thin sheet of collagen and glycoproteins produced in part by the epithelial cells themselves and in part by underlying connective tissue cells specifically, fibroblasts. The basement membrane serves to regulate cell behavior and can limit the spread of some neoplasms. In certain places, the basement membrane assumes major significance. Doctors often consider them together as colorectal cancer. When bowel movements are infrequent or difficult.

Irritable bowel syndrome IBS: Irritable bowel syndrome, also known as IBS, is an intestinal disorder that causes irritable abdominal pain or discomfort, cramping or bloating, and diarrhea or constipation. Part or all of the wall of the rectum can move out of position, sometimes coming out of the anus, when straining during a bowel movement.

Occurring mostly in children, the small intestine can collapse into itself like a telescope. It can become life-threatening if not treated. Continued Intestine Tests Capsule endoscopy: A person swallows a capsule that contains a camera. The camera takes pictures of possible problems in the small intestine, sending the images to a receiver worn on the persons belt Upper endoscopy , EGD esophagogastroduodenoscopy: A flexible tube with a camera on its end endoscope is inserted through the mouth.

The endoscope allows examination of the duodenum, stomach, and esophagus. An endoscope is inserted into the rectum and advanced through the colon. A doctor can examine the entire colon with a colonoscope. If problems are found, a traditional colonoscopy is usually needed. Fecal occult blood testing: A test for blood in the stool.

If blood is found in the stool, a colonoscopy may be needed to look for the source. An endoscope is inserted into the rectum and advanced through the left side of the colon. Sigmoidoscopy cannot be used to view the middle and right sides of the colon.

During a colonoscopy, a small piece of colon tissue may be removed for testing. A colon biopsy can help diagnose cancer, infection, or inflammation.

Intestine Treatments Antidiarrheal agents: Various medicines can slow down diarrhea, reducing discomfort. Reducing diarrhea does not slow down recovery for most diarrheal illnesses.

Over-the-counter and prescription medicines can soften the stool and reduce constipation. Medicines can relieve constipation by a variety of methods including stimulating the bowel muscles, and bringing in more water.

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