Gastrin hormone
The Alimentary tract to do its function, requires hormonal and nervous control. The gastrointestinal tract has its own nervous system which is called the enteric nervous system. This system consist of myentric plexus which is responsible for the gastrointestinal movement and the submucosal plexus which controls the gastrointestinal secretion and local blood flow. (1)
Hormones have important role in controlling gastrointestinal secretions. Most of these hormones have role in controlling the motility of some parts of the gastrointestinal tract. The major gastrointestinal hormones are gastrin, secretin and cholecystokinin.
Gastrointestinal hormones also have role in regulating the volume of the secretions in the stomach and intestine. These hormones are secreted from the gastrointestinal mucosa only when food is presented in the lumen of the gut. When these hormones are secreted, they are then absorbed into the blood so to be transfered to the glands where secretion is stimulated. This process occurs in order to increase gastric and pancreatic juices in response to food entering the stomach.(1)
Gastrin hormone is a hormone that is secreted by Gastrin cells ( G cells) by the pyloric gland which is located in the antral portion of the stomach. It is a large peptide which is secreted in two forms: G-34 which consist of 34 amino acids and its the large form of gastin, and the G-17 that consist of 17 amino acids and it is the small form of gastrin which is more abundant. It is secreted due to the presence of food in the stomach ( chemical stimulus) and by the aceTylcholine released by nerve fibers.
Gastrin hormone has a role in controlling gastric secretion. Gastrin hormone functions by binding on the secretory cells ...
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...alize stomach acidity.
It is essential for the stomach to realease the gastrin hormone so to maintain an acidity of 1.5-2 pH. Although this high acidity doesn't digest the chyme, it has many functions. The highly acidic environment kills most of the microorganisms ingested with food. It also denatures proteins and inactivates the enzymes presented in food. It is essential for activating pepsin so to do its proper function in breaking proteins, and to break plant cell wall ingested in food and the connective tissues in meat. (2)
Gastrin hormone is not only released in the stomach. It is considered to be one of the major duodenal hormones. When the G cells in the duodenum are exposed to large amounts of incompletely digested proteins, they secrete gastrin hormone so to oncrease the stomach motility and to stimulate the production of more gastric acids and enzymes. (2)
This is monitored by the cells within the Islets of Langerhans, which is located in the control (the pancreas). After skipping a meal or tough physical exercise blood glucose concentration decreases. Alpha cells in the islets detect this drop and are stimulated to secrete glucagon. Glucagon is a polypeptide hormone which influences an increase in blood glucose concentration. Glucagon travels through the bloodstream until it reaches glucagon receptors which are predominantly found in the liver, as well as, the kidneys. Glucagon stimulates the breakdown of stored glycogen to be released into the bloodstream as glucose. It also stimulates the conversion of amino acids into glucose and the breakdown of fat into fatty acids. These effectors cause an increase in blood glucose levels back towards the normal. This increase in blood glucose concentration is detected by the alpha cells which then stop the secretion of
Now the Cheetos have entered the stomach. The process of breaking down carbohydrates has already begun in the mouth and now more chemical and mechanical digestion will take place in the stomach. Once the bolus has entered the stomach, it mixes with gastric juice, starts protein digestion, and absorbs a limited amount. Here the chief cells secrete the inactive enzyme pepsinogen and the parietal calls secrete hydrochloric acid. When mixed together, they create pepsin. The pepsin works to breakdown the two grams of protein present in the Cheetos. Hormones are also present in the stomach and aid in the digestion process. The hormone, gastrin, increases the secretory activity of gastric glands. In the stomach, some salt from the Cheetos is absorbed through the wall. The Cheetos that entered the stomach has no...
Gastrointestinal tract (GIT) is the portal through which nutritive substances; vitamins, minerals and fluids enter the body. The digestive tract is more than 10 metres long from one end to the other. It is continuous starting from the mouth, passing through the pharynx and the oesophagus, to the stomach, the small and large intestines, ending in the rectum, and finally into the anus. The GI tract is divided into two main sections: the upper GI tract and the lower GI tract. Upper GIT includes the mouth, pharynx, oesophagus and stomach. The lower GI tract includes the small and large intestines and anus. The accessory organs of digestions are the gallbladder, liver and pancreas. Diseases that may occur in upper and lower GIT can be divided as oesophageal diseases, gastric diseases and intestinal diseases.
3. Stomach: Holds about 1qt of food for 3-4 hours and controls the rate at which it enters the small intestine. It also produces Chyme and Gastric Juices.
Stomach, an organ belongs to the digestive system, plays an important role in human body. This J-shaped organ can be full with one liter of food. Stomach is located on left upper part of abdominal cavity, it connects the esophagus (upper) with the small intestine (below). To the left of the stomach, there is a spleen and to the right of it, we’ve got the liver. There are four sections of the stomach: cardia, fundus, body and pyloric. To control the openings into the stomach, the gastroesophageal sphincter relaxes and allowing food leave the stomach is the function of pyloric sphincter. The stomach wall has three layers of muscles that help it contracts in all direction to break food into smaller molecules. Moreover, this organ is lined by mucus coat to neutralize acid
The endocrine system consists of six parts; pancreas hypothalamus, thyroid, pituitary gland, ovary, and adrenal gland. The pancreas is a large gland that produces hormones that regulate blood sugar; produces enzymes that break down carbohydrates, lipids, proteins, and nucleic acids; and produces sodium bicarbonate, a base that neutralizes stomach acid. The hypothalamus is a brain structure that acts as a control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature. The thyroid is a large gland in the neck that secretes (produces) hormones regulating growth through the rate of metabolism. The pituitary gland is in the base of the skull that secretes nine hormones that directly regulate many body functions and control the actions of several other endocrine glands. The ovary ( found in females) is a gonad that produces eggs. The adrenal glands are a pair of glands located above the kidneys, which produces epinephrine and norepinephrine. The endocrine system main function is to release hormones that affect activities of other cells.
An analogy that fits very well with the study of the endocrine system is that of a message in a bottle. We can think of the body as a river, and a specific hormone may be a bottle containing a message. The organs or glands mentioned above would manufacture the “bottles'; (hormones) that would be released into the river (blood stream). If there were no receptor sites for the hormones in the body, then they would continue to flow along the river and probably not make their destination. However, there are systems of receptor sites that enable specific hormones to bind in specific places. Structure also plays a major role in determining which hormones are able to bind to which receptors.
The pancreas can be divided into two sections when studying the histology. The pancreas has exocrine and endocrine functions, each with unique cell types. The exocrine pancreas serves to secrete digestive enzymes into the duodenum. Some of the specific enzymes and secreted substances are Proteases, lipase, amylase, bicarbonate, and water (Bowen, “Exocrine Secretions”). These enzymes are used to break down protein, fat, and carbohydrates respectively. The bicarbonate simply act as an acid buffer to prevent damage of the small intestine as the stomach acid must be neutralized. The enzymes are created in acinar cells and the bicarbonate is synthesized in epithelial cells surrounding pancreatic ducts (Bowen “Exocrine
The digestive system otherwise known as the gastrointestinal tract (GI tract) is a long tube which runs from the mouth to the anus. It operates to break down the food we eat from large macromolecules such as starch, proteins and fats, which can’t be easily absorbed, into readily absorbable molecules such as glucose, fatty acids and amino acids. Once broken down, these molecules can cross the cells lining the small intestine, enter into the circulatory system and be transported around the body finally being used for energy, growth and repair.
The pancreas is a 6-inch long organ in the body, located behind the stomach in the abdomen. The pancreas contains exocrine and endocrine glands that produce pancreatic juices, insulin, and hormones. Pancreatic juices, also called pancreatic enzymes, are made by the exocrine glands and released into the intestines to help with digestion. Around 95% of the pancreas is exocrine glands and ducts. The endocrine part of the pancreas are arranged in small clusters of cells called islets of Langerhans. Islets of Langerhans release insulin and glucagon into the bloodstream and those two hormones manage the level of sugar in the blood. When these two hormones are not working like they are supposed to, it often results in diabetes.
The pancreas is the chief/main factory for all of the digestive enzymes and they are secreted in the first segment/part of the small intestine. The enzymes break down proteins into protease, fats into lipase and carbohydrates into carbohydrase. Also, the pancreas produces insulin which is responsible for controlling the blood sugar and then it is secreted directly into the bloodstream. Insulin is the main/chief hormone that metabolizes
The organs of the digestive system are in two different groups. One is the alimentary canal known by as the gastrointestinal tract. It is a muscular tube that digests the food and breaks it down and absorbs the digested fragments in the lining of the blood. The organs in the gastrointestinal tract are the mouth which the food comes into the body and out of the body by peristalsis. The pharynx called the throat which receives the food; this is where swallowing occurs, while the esophagus transports the food to the stomach. The esophagus is a muscular tube that food is pushed into by contractions caused by peristalsis. Also food is kept in the stomach by the esophageal sphincter (LES), which opens to let food pass into the stomach and closes to keep it there. Now the stomach it is the storage system and grinder of the digestive system. It secretes acids and enzymes that break down the food. Those that cannot be broken down are passed through the small intestine to be taken care of. The small intestine is made up of three sections the duodenum responsible for the breakdown of the food, jejunum, and ileum which are responsible for the absorption of food; it also has enzymes that also break down food released by the pancreas and liver. The large intestine is where the waste goes to the anus. The accessory digestive organs are the teeth, tongue, gallbladder, salivary glands, pancreas, and liver. The teeth help to chew the food while the tongue helps to reposition the food to teeth to be chewed. The salivary glands are associated with the section of saliva which cleans the mouth, dissolves food chemicals to be tasted, moisten foods, and enzymes to break down starchy food. The pancreas, liver, gallbladder are responsible for the secretio...
http://kidshealth.org/kid/cancer_center/HTBW/digestive_system.html ( I didnt copy direct quotes, however I had used the idea of the beginning in my research on the digestive system to help the reader better understand the system)
The pancreas is one of the essential organs in the human body and belongs in the Digestive system. Out of all the internal organs, the pancreas is unique because the pancreas plays a role in both the endocrine gland and the exocrine gland. This means that the pancreas is a dual function gland in which is the reason why the pancreas is such a vital part of the digestive system. This research paper will talk about the anatomy, physiology, and the important functions the pancreas play to maintain homeostasis.
The pancreas, in addition to its digestive process has two important hormones, Insulin and Glucagon which are important for the maintenance of blood glucose level at a narrow range. Not only glucose, but also they are important for protein and lipid metabolism. Glucagon is secreted by the alpha cells of the islet of Langerhans and Insulin is secreted by the beta cells of Langerhans. Both are secreted to portal vein. (8)