Digestive System: Facts, Function & Diseases
Also called gall. Radionuclide scanning is a non-invasive screening technique used for locating sites of acute bleeding, especially in the lower GI tract. This procedure
After an hour or two of this process, a thick semi-liquid paste, called chyme, forms. Swallowing pushes chewed food into the esophagus, where it passes through the oropharynx and hypopharynx.
Emesis, or vomiting, is elimination of food by forceful expulsion through the mouth. It is often in response to an irritant that affects the digestive tract, including but not limited to viruses, bacteria, emotions, sights, and food poisoning. This forceful expulsion of the food is due to the strong contractions produced by the stomach muscles.
A good working knowledge of the system and how it carries out its functions is necessary for the effective management of the poultry flock and, therefore, a study of the digestive system and the process of digestion and metabolism is an important facet in the study of poultry husbandry. When a piece of the small intestine is immersed in water it takes on a very velvety appearance because of the presence of villi – long flattened, fingerlike projections that extend into the lumen (inside) of the intestine like flexible fingers. The villi are very actively involved in the absorption process. A single layer of columnar epithelium together with goblet cells covers the lining.
The gallbladder is used to store and recycle excess bile from the small intestine so that it can be reused for the digestion of subsequent meals. The liver is a roughly triangular accessory organ of the digestive system located to the right of the stomach, just inferior to the diaphragm and superior to the small intestine. The liver weighs about 3 pounds and is the second largest organ in the body. The stomach is a muscular sac that is located on the left side of the abdominal cavity, just inferior to the diaphragm.
Inside this tube 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.
Study of the digestive system
Insulin sends a signal to the bodyâ€™s cells to remove glucose from the blood by transporting it into cells and within the cell to use glucose to make energy or for building macromolecules. In the case of muscle tissue and the liver, insulin sends the biological message to store glucose away as glycogen. The presence of insulin in the blood signifies to the body that it has just been fed and to use the fuel.
Following Food from Mouth to Anus
- These materials are propelled into the colon, where they remain, usually for a day or two, until the feces
- As the time after a meal lengthens, glucose levels decrease in the blood.
- It includes both the voluntary process of swallowing and the involuntary process of peristalsis.
- A brain reflex triggers the flow of saliva when we see or even think about food.
- examples of these disorders are.
- In the duodenum, other enzymes – trypsin, elastase, and chymotrypsin – act on the peptides, reducing them to smaller peptides.
The lips break the food down into smaller pieces. In the pharynx, the food is lubricated by mucus secretions for easier passage. The esophagus adds calcium carbonate to neutralize the acids formed by food matter decay. Temporary storage occurs in the crop where food and calcium carbonate are mixed.
Digestive System Processes and Regulation
The pancreas secretes an incredibly strong digestive cocktail known as pancreatic juice, which is capable of digesting lipids, carbohydrates, proteins and nucleic acids. By the time food has left the duodenum, it has been reduced to its chemical building blocks-fatty acids, amino acids, monosaccharides, and nucleotides. Almost all of the carbohydrates, except for dietary fiber and resistant starches, are efficiently digested and absorbed into the body.
Upon entering the esophagus, peristalsis (wave-like contractions) of smooth muscle carries the bolus toward the stomach. Two layers of smooth muscle, the outer longitudinal (lengthwise) and inner circular, contract rhythmically to squeeze food through the esophagus.
The enzyme pepsin plays an important role in the digestion of proteins by breaking them down into peptides, short chains of four to nine amino acids. In the duodenum, other enzymes – trypsin, elastase, and chymotrypsin – act on the peptides, reducing them to smaller peptides. These enzymes are produced by the pancreas and released into the duodenum where they also act on the chyme.
The small intestine is a long, thin tube about 1 inch in diameter and about 10 feet long that is part of the lower gastrointestinal tract. It is located just inferior to the stomach and takes up most of the space in the abdominal cavity.
The digestible carbohydrates are broken into simpler molecules by enzymes in the saliva, in juice produced by the pancreas, and in the lining of the small intestine. The liver produces yet another digestive juice – bile. The bile is stored between meals in the gallbladder.