Q. What is the stomach?
A.If the esophagus is a conduit with a valve at each end, the stomach can be likened to a storage and processing facility, where the food is prepared for digestion.
This food warehouse can accommodate anything from a light afternoon snack to a five-course meal. Without this large storage capacity, people would have to eat small, frequent meals, and they’d be unable to drink large quantities of liquids at any given time.
But the stomach doesn’t just hold food: Muscles in the lower stomach also mix that food into a soft mush. This process is aided by the liquids we drink and by saliva, hydrochloric acid, and the enzyme pepsin. Hydrochloric acid and pepsin, produced by the glands that line the stomach, help break down proteins into their constituent amino acids. The stomach mucosa has a defense system, including an overlying layer of mucus and bicarbonate, to protect itself. After mixing, a once-palatable meal is reduced to a thick liquid called chyme.
The other important function of the stomach, apart from storing and then grinding and mashing the food, is to deliver the resulting chyme to the small intestine in amounts it can handle. Too large a load could overwhelm the intestine’s ability to absorb nutrients. Peristaltic contractions drive this mixture through the pyloric sphincter — another muscular gate in the digestive tract — and into the duodenum, the first part of the small intestine. The process of delivering chyme to the intestine occurs over time and is affected by numerous factors: a variety of hormones, what’s been ingested (fluids move more quickly than solids), and external considerations such as emotions and physical exercise. All can either delay or stimulate stomach emptying.
The involuntary contractions that push stomach contents along are governed by nerves in the stomach wall (see The Stomach Wall ), which transmit electrical impulses to the brain. The nerves that carry impulses from the GI tract, called visceral nerves, recognize stretching, pulling, or expansion (distention) of the muscles in the walls of the digestive tract. Intestinal pain can result when these sensations are excessive.
When you haven’t eaten for a while and your stomach is empty, it initiates a series of rhythmic contractions known as hunger pangs. They serve as a signal to the brain: "Feed me!" These contractions explain stomach noises, which also can be caused when air or fluid is moving around inside. Once you’ve eaten, it takes about two hours for the muscular stomach to reduce a typical meal to a liquid and have it ready to move along to the small intestine. A high-protein meal can take an extra hour or two. A high-fat meal can take up to six hours.
Any personal health questions or problems mental or physical or before starting any diet or exercise program.Please consult your physician !
Wishing You Great Health!
Glen Edward Mitchell
Any questions? Ask Glen!