digestive

digestive

 [dĭ-jes´tiv]

pertaining to digestion.

digestive system the organs that have as their particular function the ingestion, digestion, and absorption of food or nutritive elements. They include the mouth, teeth, tongue, pharynx, esophagus, stomach, and intestines. The accessory organs of digestion, which contribute secretions important to digestion, include the salivary glands, pancreas, liver, and gallbladder. (See also color plates.)

Mouth. The mouth is the entrance to the alimentary canal; in it the teeth, tongue, and jaws begin the process of digestion by mastication. saliva is secreted into the mouth by three separate pairs of glands (the salivary glands) located under the tongue, inside the lower jaw, and in the cheek. Saliva softens and lubricates the food, and dissolves some of it; it also contains an enzyme called ptyalin that begins the conversion of starches into sugar. Saliva also moistens the inside of the mouth, the tongue, and the teeth, and rinses them after the food has departed on the next stage of its journey.

Four passageways meet at the back of the throat: the oral and nasal passages, the larynx, and the esophagus. In the act of swallowing, the entrances to the nasal passages and the larynx are each sealed off momentarily by the soft palate and the epiglottis, so that the food can pass into the esophagus without straying into the respiratory tract.

Stomach. Propelled by rhythmic muscular contractions called peristalsis, the food moves rapidly through the esophagus, past the cardiac sphincter (a circular muscle at the base of the esophagus) and into the stomach. Here the peristaltic motions are stronger and more frequent, occurring at the rate of three per minute, churning, liquefying, and mixing the foods with the gastric juice. In the juice are the enzymes pepsin and lipase and, in infants, rennin; a secretion called mucin, which coats and protects the stomach lining; and hydrochloric acid. Together the pepsin and hydrochloric acid begin the splitting of the proteins in the food. The lipase in the stomach is a rather weak fat-splitting enzyme, able to act only on fats that are already emulsified, such as those in cream and the yolk of egg; the intestine has a stronger lipase, and it is there that most fats are digested.

The average adult stomach holds about 1.5 liters. The stomach reaches its peak of digestive activity nearly 2 hours after a meal and may empty in 3 to 4½ hours; a heavy meal may take as long as 6 hours to pass into the small intestine.

Small Intestine. The food leaves the stomach in the form of chyme, a thick, liquid mixture. It passes through the pylorus, a sphincter muscle opening from the lower part of the stomach into the duodenum. This sphincter is closed most of the time, opening each time a peristaltic wave passes over it. The stomach is much wider than the rest of the canal and also has a J-shaped curve at its bottom, so that the passage of food through the pylorus is automatically slowed until the food is of the right consistency to flow through the narrow opening into the intestine.

The small intestine is about 6 meters (20 feet) long. The lining of the small intestine has deep folds and fingerlike projections called villi that give it a surface of about 9 square meters (100 square feet) through which absorption of food can take place.

The duodenum, a C-shaped curve with a length of about 25 cm (10 in), is the first and widest part of the small intestine. Into it flows the pancreatic juice, with enzymes that break down starch, protein, and fats. The common bile duct also empties into the duodenum. The bile emulsifies fats for the action of the fat-splitting enzymes.

Just below the duodenum is the jejunum, the longest portion of the small intestine, and beyond that is the ileum, the last and narrowest section of the small intestine. Along this whole length, carbohydrates, proteins, and fats are broken down into sugars, amino acids, fatty acids, and glycerin. The lining of the small intestine absorbs these nutrient compounds as rapidly as they are produced. The bulky and unusable parts of the diet pass into the large intestine.

Large Intestine. At the junction of the small and large intestines is the ileocecal valve, so called because it is at the end of the ileum and the beginning of the cecum. A small blind tube called the vermiform appendix is attached to the cecum. The longer part of the large intestine is called the colon and is divided into the ascending, transverse, and descending colon, and the sigmoid flexure, an S-shaped bend at the distal end of the colon. The sigmoid colon empties into the rectum.

Along the 1.7 meters (5.5 feet) or so of the large intestine, the liquid in the waste is gradually reabsorbed through the intestinal walls. Thus the waste is formed into fairly solid feces and pushed down into the rectum for eventual evacuation. This takes from 10 to 20 hours. The evacuation consists of bacteria, cells cast off from the intestines, some mucus, and such indigestible substances as cellulose. The normal dark brown color of the feces is caused by bile pigments.

Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

di·ges·tive

(di-jes'tiv, dī-),

1. Relating to digestion.

2. Synonym(s): digestant (2)

Farlex Partner Medical Dictionary © Farlex 2012

digestive

(dī-jĕs′tĭv, dĭ-)

adj.

1. Relating to or aiding digestion.

2. Functioning to digest food.

n.

A substance that aids digestion.

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di·ges′tive·ly adv.

di·ges′tive·ness n.

The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

di·ges·tive

(di-jes'tiv)

1. Relating to digestion.

2. Synonym(s): digestant (2) .

Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Patient discussion about digestive

Q. My aunt suffered from digestive disorder a few months back. My aunt suffered from digestive disorder a few months back. First we were told that this symptom reveal that she is suffering from fibromyalgia. Later another doctor diagnosed her and said that she is not affected by fibromyalgia. So we like to know actually what is fibromyalgia sometimes mistaken for?

A. I have received similar questions from many of my friends so you are not the first person to have such question, so don’t worry. Usually fibromyalgia is initially mistaken for several other conditions, including Lyme disease, lupus, depression and rheumatoid arthritis to name just a few illnesses. Other conditions for which fibromyalgia is occasionally mistaken include digestive disorders, sleep disorders and thyroid problems. Often, it is because the various symptoms of fibromyalgia are so similar to the symptoms of other disorders that many FMS patients do not receive a proper diagnosis for many years. And this is also why it is especially critical to be seen by either a rheumatologist or a pain specialist to ensure a proper diagnosis, and to rule out other conditions.

Q. It feels like I cannot breath properly, my chest feels heavy and Whenever i eats something it gets even more. If i don't eat much i get gases problem. I am regularly having constipation if i don't take proper medicine. Mostly i have been diagnosed as Digestive System problem, stomach problem, dryness in body and no Problem with my breathing system just cause of gases which causes my chest to remain heavy. I am worried because i never gets my real power in breathing and my digestive system is not getting well. Kindly suggest.

A. I take milk regularly have no problem with it nor with any specific food or i have never tried to look at this aspect. However i do feel stomach problem with foods heavy for stomach like burger or too much oily things..

Q. What is the connection between Acid Reflux and Autism? I heard about a digestive issue called Acid reflux. Some people say that this is related to Autism. What is the connection between Acid Reflux and Autism?

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