Digestive System

Digestion is the breaking down of food in the body, into a form that can be absorbed and used or excreted. It is also the process by which the body breaks down food into smaller components that can be absorbed by the blood stream.

In order to use the food we eat, our body has to break the food down into smaller molecules that it can process; it also has to excrete waste.

The digestive process begins in the mouth. Food is partly broken down by the process of chewing and by the chemical action of salivary enzymes (these enzymes are produced by the salivary glands and break down starches into smaller molecules).

The digestive system is made up of the digestive tract, a series of hollow organs joined in a long, twisting tube from the mouth to the anus, and other organs that help the body break down and absorb food.

Organs that make up the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine, also called the colon, rectum, and anus. Inside these hollow organs is a lining called the mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that produce juices to help digest food. The digestive tract also contains a layer of smooth muscle that helps break down food and move it along the tract.

Two solid digestive organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes called ducts. The gallbladder stores the liver’s digestive juices until they are needed in the intestine. Parts of the nervous and circulatory systems also play major roles in the digestive system.

Mechanical and chemical digestion begin in the mouth where food is chewed, and mixed with saliva to break down starches. The stomach continues to break food down mechanically and chemically through the churning of the stomach and mixing with enzymes. Absorption occurs in the stomach and gastrointestinal tract, and the process finishes with excretion.

The stomach is a small,'C'-shaped pouch with walls made of thick, elastic muscles, which stores and helps break down food. Food enters the stomach through the cardiac orifice where it is further broken apart and thoroughly mixed with gastric acid, pepsin and other digestive enzymes to break down proteins. The enzymes in the stomach also have an optimum, meaning that they work at a specific pH and temperature better than any others. The acid itself does not break down food molecules, rather it provides an optimum pH for the reaction of the enzyme pepsin and kills many microorganisms that are ingested with the food. It can also denature proteins. This is the process of reducing polypeptide bonds and disrupting salt bridges which in turn causes a loss of secondary, tertiary or quaternary protein structure. The parietal cells of the stomach also secrete a glycoprotein called intrinsic factor which enables the absorption of vitamin B-12. Other small molecules such as alcohol are absorbed in the stomach, passing through the membrane of the stomach and entering the circulatory system directly. Food in the stomach is in semi-liquid form, which upon completion is known as chyme.

Digestive System

Further Information Regarding Digestive System

Ulcerative Colitis Treatment Reduces Need for Surgery
A new study led by Mayo Clinic researchers has found that ulcerative colitis patients had a 41 percent reduction in colectomy after a year when treated with infliximab, according to a study published in the October 2009 issue of Gastroenterology.

Fecal Incontinence - Loss of Bowel Control Information
Fecal incontinence is the inability to control your bowels. When you feel the urge to have a bowel movement, you may not be able to hold it until you get to a toilet. Or stool may leak from the rectum unexpectedly, sometimes while passing gas.

Test Diagnoses Chronic Allergic Condition
Scientists at Mayo Clinic have invented a quick new way to diagnose a puzzling digestive condition that has rocketed from a virtually "unheard of" disease to one that, in less than a decade, has become increasingly common. Incidence of eosinophilic esophagitis, also called EoE, or allergic esophagitis, has been on the rise since its initial identification in the late 1980s.

Pseudomembranous Entercolitis - Facts and Treatment
Pseudomembranous Colitis involves an infection of the person's large intestine, with an overgrowth of the Clostridium Difficile Bacteria. The diarrhea persons experience secondary to antimicrobials may be classified into four different categories; they are classified according to the basis of the changes which happen in the person's colon. One of the changes produces pseudomembrane formation of the wall of the person's large intestine.

Stomach Ulcers - Definition, Causes, Symptoms, Diagnosis, and Treatment
A stomach ulcer involves an erosion in a person's gastrointestinal tract. An ulcer may also be referred to as a, 'Peptic Ulcer.' The most common form of ulcer is a duodenal ulcer which occurs within the first foot of a person's small intestine, just beyond their stomach. Ulcers which form in a person's stomach are referred to as, 'Gastric Ulcers.'

Diverticulitis - Definition, Causes, Symptoms, Diagnosis, and Treatment
Diverticulitis involves a condition where diverticuli in the person's colon rupture, resulting in an infection of the tissues surrounding their colon. Pressure within a person's colon may cause pockets of tissue, referred to as, 'sacs,' to push out from the walls of their colon as they age. A small sac may push outward from their colon wall called a, 'diverticulum;' several of these sacs are referred to as, 'diverticula.' These diverticula may occur throughout a person's colon, although they most commonly occur near the end of the left colon called the, 'Sigmoid Colon.' When a person has the condition where these diverticula are present, the condition is called, 'Diverticulosis.'

Ulcerative Colitis - Definition, Causes, Symptoms, Diagnosis, and Treatment
Ulcerative Colitis involves a chronic inflammation of the person's large intestine, also referred to as their, "colon." The colon is a part of a person's digestive system where waste material is stored. Persons with ulcerative colitis experience inflammation and ulcers of the inner lining of their colon that lead to diarrhea, rectal bleeding, and abdominal pain.

Environmental Pollution Increases Risk of Liver Disease
A new study is the first to show that there is a previously unrecognized role for environmental pollution in liver disease in the general U.S. adult population. This work builds upon the groups' previous research demonstrating liver disease in highly-exposed chemical workers.

Gastric Bypass Surgery in Obese Patients
Superobese gastric bypass patients appear to have improvements in quality of life and obesity-related co-existing conditions, and despite losing weight remain obese after surgery, according to a report in the April issue of Archives of Surgery, one of the JAMA/Archives journals.

Digestive System - Gastric Bypass Surgery
We tend to use the term gastric bypass surgery somewhat loosely these days and include both true bypass operations such as the Roux-En-Y and popular and less radical forms of weight loss surgery such as gastric banding.

Digestive System Disorders
Digestive system disorders happen when there is a faulty function during the process of digestion which prevents some part of the digestive system from working as it should do. There are many common digestive system disorders.

Digestive System - Amazing Facts
We all understand that the digestive system is simply the process that our body uses to glean the benefits of the foods we eat. Some of us have more knowledge about it than others, and that often comes from the type of education we are exposed to.