Peristalsis
In much of a digestive tract such as the human gastrointestinal tract, smooth muscle tissue contracts in sequence to produce a peristaltic wave, which propels a ball of food (called a bolus while in the esophagus and upper gastrointestinal tract and chyme in the stomach) along the tract. Peristaltic movement comprises relaxation of circular smooth muscles, then their contraction behind the chewed material to keep it from moving backward, then longitudinal contraction to push it forward. Earthworms use a similar mechanism to drive their locomotion, and some modern machinery imitates this design. Trace the flow of blood from the left heart to the digestive tract, to the liver, and back to the right heart by listing the names of the major vessels it flows through in appropriate sequence. 1. Vessels gather up nutrients from the digestive tract 2. Endocrine and nervous system regulate digestive system-Keep food moving through GI tract-Secrete hormones that: • Neutralize pH • Release bile • Move food from stomach to small intestine • Etc. Buccal phase – bolus is forced into the oropharynx. Pharyngeal-esophageal phase – controlled by the medulla and lower pons, all routes except into the digestive tract are sealed off, peristalsis moves food through the pharynx to the esophagus. The esophagus carries solids and liquids from the pharynx to the stomach, passes through esophageal hiatus in diaphragm. Stomach.  The digestive system is made up by the alimentary canal, or the digestive tract, and other abdominal organs that play a part in digestion such as the liver and the pancreas. The alimentary canal is the long tube of organs that runs from the mouth (where the food enters) to the anus (where indigestible waste leaves). Muscularis: The muscularis is responsible for segmental contractions and peristaltic movement in the GI tract. The muscularis is composed of two layers of muscle: an inner circular and outer longitudinal layer of smooth muscle. Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. When the pyloric sphincter valve opens, chyme enters the duodenum where it mixes with digestive enzymes from the pancreas and bile juice from the liver and then passes through the small intestine, in which digestion continues. When the chyme is fully digested, it is absorbed into the blood. After food is chewed into a bolus, it is swallowed and moved through the esophagus. Smooth muscles contract behind the bolus to prevent it from being squeezed back into the mouth. Then rhythmic, unidirectional waves of contractions work to rapidly force the food into the stomach. Peristaltic movement comprises relaxation of circular smooth muscles, then their contraction behind the chewed material to keep it from moving backward, then longitudinal contraction to push it forward. Earthworms use a similar mechanism to drive their locomotion, and some modern machinery imitates this design. Gastrointestinal motility refers to the contraction of the smooth muscles of the gastrointestinal tract. The gastrointestinal tract is commonly divided into 5 parts: the mouth, esophagus, stomach, small intestine, and large intestine (colon). GI motility is regulated in 3 ways: 1  Reflexes that originate outside the digestive system (called long reflexes). 2  Reflexes that originate inside the digestive system (called the enteric nervous system or short reflexes). 3  Gastrointestinal (GI) Peptides. The large, hollow organs of the digestive tract contain a layer of muscle that enables their walls to move. The movement of organ walls can propel food and liquid through the system and also can mix the contents within each organ. Food moves from one organ to the next through muscle action called peristalsis. Organs that make up the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine-also called the colon-rectum, and anus. Inside these hollow organs 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. The digestive tract also contains a layer of smooth muscle that helps break down food and move it along the tract. Two “solid” digestive organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes called duct Digestion involves mixing food with digestive juices, moving it through the digestive tract, and breaking down large molecules of food into smaller molecules. Digestion begins in the mouth, when you chew and swallow, and is completed in the small intestine. Organs that make up the digestive tract are the mouth, esophagus, stomach, small intestine, large intestine-also called the colon-rectum, and anus. Inside these hollow organs 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. The digestive tract also contains a layer of smooth muscle that helps break down food and move it along the tract. Two “solid” digestive organs, the liver and the pancreas, produce digestive juices that reach the intestine through small tubes called ducts
https://en.wikipedia.org/wiki/Peristalsis https://quizlet.com/19815968/chapter-3-objectives-flash-cards/ http://www.austincc.edu/rfofi/BIO2305/2305LecNotes/2305Digestive.doc https://en.wikibooks.org/wiki/Human_Physiology/The_gastrointestinal_system https://en.wikipedia.org/wiki/Digestion https://en.wikipedia.org/wiki/Peristalsis http://www.austincc.edu/apreview/EmphasisItems/GImotility.html http://digestive.templehealth.org/content/YourDigestiveSystem.htm http://digestive.templehealth.org/content/YourDigestiveSystem.htm
what mechanism moves food through the gastrointestinal tract