23.4 The Stomach – Anatomy and Physiology


Posted On Oct 3 2018 by

The small intestine absorbs most of the nutrients in your food, and your circulatory system passes them on to other parts of your body to store or use. Special cells help absorbed nutrients cross the intestinal lining into your bloodstream.

The endoscope is a flexible instrument that can be inserted through the mouth or rectum. The instrument allows the doctors to see inside the esophagus, stomach, duodenum(esophagoduodenoscopy), sigmoid colon(sigmoidoscopy), and rectum(rectoscopy, to collect small samples of tissues, take pictures, and stop the bleeding. There is a new procedure out using a long endoscope that can be inserted during surgery to locate a source of bleeding in the small intestine. Benign tumors or cancer of the stomach may also cause bleeding. These disorders don’t usually produce massive bleeding. The most common source of bleeding usually occurs from ulcers in the duodenum.

Bleeding in the gastrointestinal tract doesn’t always mean you have a disease, it’s usually a symptom of a digestive problem. The cause of the bleeding may not be that serious, it could be something that can be cured or controlled such as hemorrhoids. However, locating the source of the bleeding is very important. The gastrointestinal tract contains many important organs like the esophagus, stomach, small intestine, large intestine or colon, rectum, and anus. Bleeding can come from one or more of these area from a small ulcer in the stomach, or a large surface like the inflammation of the colon.

Milk contains yet another type of sugar, lactose, which is changed into absorbable molecules by an enzyme called lactase, also found in the intestinal lining. Digested molecules of food, as well as water and minerals from the diet, are absorbed from the cavity of the upper small intestine.

The villi contain large numbers of capillaries which take the amino acids and glucose produced by digestion to the hepatic portal vein and the liver. The functions of a small intestine is, the digestion of proteins into peptides and amino acids principally occurs in the stomach but some also occurs in the small intestine. Peptides are degraded into amino acids; lipids (fats) are degraded into fatty acids and glycerol; and carbohydrates are degraded into simple sugars.

It connects the pharynx, which is the body cavity that is common to both the digestive and respiratory systems behind the mouth, with the stomach, where the second stage of digestion is initiated (the first stage is in the mouth with teeth and tongue masticating food and mixing it with saliva). Also known as the gastrointestinal (GI) tract, the digestive system begins at the mouth, includes the esophagus, stomach, small intestine, large intestine (also known as the colon) and rectum, and ends at the anus. The entire system – from mouth to anus – is about 30 feet (9 meters) long, according to the American Society of Gastrointestinal Endoscopy (ASGE). As soon as food enters your stomach, your stomach lining releases enzymes that start breaking down proteins in the food. Your stomach lining also secretes hydrochloric acid, which creates the ideal conditions for the protein-digesting enzymes to work.

The pylorus, which holds around 30 mL (1 fluid ounce) of chyme, acts as a filter, permitting only liquids and small food particles to pass through the mostly, but not fully, closed pyloric sphincter. In a process called gastric emptying, rhythmic mixing waves force about 3 mL of chyme at a time through the pyloric sphincter and into the duodenum. Release of a greater amount of chyme at one time would overwhelm the capacity of the small intestine to handle it. The rest of the chyme is pushed back into the body of the stomach, where it continues mixing.

does stomach acid enters the small intestine

Some food material is passed from the small intestine to the large intestine, or colon. In the colon, chyme is acted upon by bacteria that break down the proteins, starches, and some plant fibres not totally digested by the other organs.

When the stomach is empty it is about the size of one fifth of a cup of fluid. When stretched and expanded, it can hold up to eight cups of food after a big meal. On the inside of the stomach there are folds of skin call the gastric rugae. Gastric rugae make the stomach very extendable, especially after a very big meal.

greater quantities of food-such as at holiday dinner-you stretch the stomach more than when you eat less. Hormones control the different digestive enzymes that are secreted in the stomach and the intestine during the process of digestion and absorption. For example, the hormone gastrin stimulates stomach acid secretion in response to food intake. The hormone somatostatin stops the release of stomach acid. In reaction to the smell, sight, or thought of food, like that shown in Figure 15.20, the first hormonal response is that of salivation.

Treatment involves medications or, in severe cases, surgery. Bile reflux and gastric acid reflux are separate conditions. Whether bile is important in GERD is controversial. Bile is often a suspected of contributing to GERD when people respond incompletely or not at all to powerful acid-suppressant medications.

The acid is required to separate vitamin B12 from food. Intrinsic factor is necessary for the absorption of vitamin B12 in the small intestine. Doctors can prescribe a way to overcome these problems if no gastric juice is made. Another potential problem with achlorhydria (no stomach acid) is bacterial overgrowth in the stomach.

When the beneficial organisms die they are replaced by harmful organisms, such as yeasts and parasites, the most common being Candida albicans. This leads to changes in the intestinal wall which produce leaky gut syndrome, which allows many toxic chemicals to be introduced into the bloodstream. As a result, the entire toxic load of the body is increased, causing a bigger burden on the liver, kidneys and other body organs.

Two types of luminal acid-induced programs to ensure tissue homeostasis in the esophagus, stomach and duodenum. Either type of program is under the control of molecular acid sensors (AS) on sensory neurons. CNS, central nervous system; ENS, enteric nervous system; LES, lower esophageal sphincter. You also have an enteric nervous system (ENS)-nerves within the walls of your GI tract.

does stomach acid enters the small intestine

Last Updated on: September 25th, 2019 at 12:36 pm, by


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