Your Digestive System
The cells are filled with secretory granules containing the precursor digestive enzymes (mainly trypsinogen, chymotrypsinogen, pancreatic lipase, and amylase) that are secreted into the lumen of the acinus. These granules are termed zymogen granules (zymogen referring to the inactive precursor enzymes.) It is important to synthesize inactive enzymes in the pancreas to avoid auto degradation, which can lead to pancreatitis. The hormone gastrin causes an increase in the secretion of HCL, pepsinogen and intrinsic factor from parietal cells in the stomach.
Once foods are broken into small enough parts, your body can absorb and move the nutrients to where they are needed. Your large intestine absorbs water, and the waste products of digestion become stool. Nerves and hormones help control the digestive process.
How Does Digestion Work?
Sometimes a person doesn’t even know they are bleeding. When this happens, it is called hidden, or occult bleeding. Simple tests can detect hidden blood in the stool.
The pyloric sphincter controls this exit of partially-digested food from the stomach into the duodenum, so that only small amounts are passed through at a time.
A peptic ulcer can block the pyloric valve so that it doesn’t open enough to allow the stomach to empty as quickly as it should. Stagnant food in the stomach can lead to increased gastric pressure and allow bile and stomach acid to back up into the esophagus.
The stomach is a muscular pouch located in the upper left abdomen, and the duodenum leads off the stomach, forming the beginning of the small intestine. Even more important, though, are the intrinsic (inside) nerves, which make up a very dense network embedded in the walls of the esophagus, stomach, small intestine, and colon. The intrinsic nerves are triggered to act when the walls of the hollow organs are stretched by food.
Inflammatory bowel disease is the chronic inflammation of the intestines, which usually affects older children, teens and adults. There are two major types, ulcerative colitis and Crohn’s disease and indeterminate colitis, which occurs in 10-15% of patients. Ulcerative colitis usually affects just the rectum and large intestine, while Crohn’s disease can affect the whole gastrointestinal tract from mouth to anus along with some other parts of the body.
- The cephalic phase of gastric secretion occurs before food enters the stomach due to neurological signals.
- Most of the digestion of the protein, fats and carbohydrate in the chyme is done by the enzymes in the duodenum, before the resultant mixture is passed further into the small intestine.
- Importantly, the acidity of the chyme is what triggers the pyloric sphincter to open.
If the sphincter doesn’t work properly, food and acid may move up into the esophagus, creating a burning sensation. Stomach acid can also aggravate ulcers, making them more painful.
The gastric phase begins once the food arrives in the stomach. It builds on the stimulation provided during the cephalic phase.
and is pushed down into the stomach by the process of peristalsis (involuntary wavelike muscle contractions along the G.I. tract). At the end of the esophagus there is a sphincter that allows food into the stomach then closes back up so the food cannot travel back up into the esophagus. Digestion begins in the mouth. A brain reflex triggers the flow of saliva when we see or even think about food. Saliva moistens the food while the teeth chew it up and make it easier to swallow.
It is possible to return good health to your GI tract by improving digestion, consuming the right amount of fiber, and cutting out junk food and refined sugars. Poor digestion, poor absorption, and bacterial imbalance can be traced to many chronic conditions. Every organ in the body receives nutrients from the GI tract; if the GI tract is malfunctioning then the whole body suffers.
It avoids the normal digestive process and goes right into the bloodstream. About 20 percent of the alcohol consumed is absorbed in the stomach, and about 80 percent is absorbed in the small intestine. This mucus layer also protects the mucosa from digestive enzymes in the lumen, but why dont the enzymes do damage before they are secreted from the exocrine cells of the mucosa?. Because they are never present within the cells!. The cells synthesize and secrete proenzymes that are larger than the active enzymes.
Gastrin also stimulates growth of the stomach lining and increases the muscle contractions of the gut to aid digestion. Heavy drinking over a period of years can damage the liver. Some of this damage comes from free radicals, a group of molecules that are highly reactive.
The secretion of gastrin is stimulated by food arriving in the stomach. The secretion is inhibited by low pH. Gastrin is in the stomach and stimulates the gastric glands to secrete pepsinogen (an inactive form of the enzyme pepsin) and hydrochloric acid. The secretion of gastrin is stimulated by food arriving in the stomach. The intestinal phase occurs in the duodenum as a response to the arriving chyme, and it moderates gastric activity via hormones and nervous reflexes.
The muscles of the small intestine mix food with digestive juices from the pancreas, liver, and intestine, and push the mixture forward for further digestion. The walls of the small intestine absorb water and the digested nutrients into your bloodstream.