Digestive System Processes and Regulation Learning Objectives By the end of this section, you will be able to: List in order the organs of the alimentary canal. Describe the types of movements that occur in the digestive system. Distinguish between physical and chemical digestion.
Describe the neural and hormonal regulation of digestion. Visit this site for an overview of digestion of food in different regions of the digestive tract. Note the route of non-fat nutrients from the small intestine to their release as nutrients to the body. Critical Thinking Questions Offer a theory to explain why segmentation occurs and peristalsis slows in the small intestine.
It has been several hours since you last ate. Walking past a bakery, you catch a whiff of freshly baked bread. What type of reflex is triggered, and what is the result? Show Answers The majority of digestion and absorption occurs in the small intestine. By slowing the transit of chyme, segmentation and a reduced rate of peristalsis allow time for chemical digestion and nutrient absorption to occur. The smell of food initiates long reflexes, which result in the secretion of digestive juices.
Licenses and Attributions. CC licensed content, Original. Ingests food Mechanical digestion: chews and mixes food Begins chemical digestion of carbohydrates Moves food into the pharynx Begins chemical digestion of lipids via lingual lipase.
Moistens and dissolves food, allowing you to taste it Cleans and lubricates the teeth and oral cavity Has some antimicrobial activity. Mechanical digestion: Churns food with gastric juices to form chyme Begins chemical digestion of proteins Releases food into the duodenum as chyme Absorbs some fat-soluble substances for example, alcohol, aspirin Possesses antimicrobial functions.
Stimulates protein-digesting enzymes Secretes intrinsic factor required for vitamin B 12 absorption in small intestine. Mixes chyme with digestive juices Bile from the liver emulsifies fat in chyme to maximize the effectiveness of lipases Most chemical digestion occurs in the small intestine Propels food at a rate slow enough for digestion and absorption Absorbs breakdown products of carbohydrates, proteins, lipids, and nucleic acids, along with vitamins, minerals, and water.
Liver: produces bile salts, which emulsify lipids, aiding their digestion and absorption Gallbladder: stores, concentrates, and releases bile Pancreas: produces digestive enzymes and bicarbonate. Bicarbonate-rich pancreatic juices help neutralize acidic chyme and provide optimal environment for enzymatic activity.
Further breaks down food residues Absorbs most residual water, electrolytes, and vitamins produced by enteric bacteria Propels feces toward rectum Eliminates feces. Also, peristalsis mainly occurs in the esophagus , while segmentation mainly occurs in the small and large intestine. Peristalsis and segmentation are two types of muscular movements that occur in the gastrointestinal tract.
They are responsible for the movement of food through the gastrointestinal tract. What is Peristalsis — Definition, Characteristics, Importance 2. What is Segmentation — Definition, Characteristics, Importance 3. Peristalsis is a radially symmetrical muscular movement responsible for the propagation of materials. Generally, it is more common in the esophagus of the gastrointestinal tract, propelling a ball of food from the mouth to the stomach.
Basically, the contraction of the circular muscles of the wall of the esophagus is responsible for peristalsis. Moreover, peristalsis produces a one-way movement. M—Malformation should bring to mind congenital pyloric stenosis, malrotation, hernias, and volvulus. Background Weak and absent esophageal peristalsis are frequently encountered esophageal motility disorders , which may be associated with dysphagia and which may contribute to gastroesophageal reflux disease.
When an ileus occurs , it stops peristalsis and prevents the passage of food particles, gas, and liquids through the digestive tract. If people continue to eat solid food, it can lead to a backlog of food particles, which may cause full or partial obstruction of the intestines. Unlike the small intestine, the large intestine produces no digestive enzymes. Chemical digestion is completed in the small intestine before the chyme reaches the large intestine.
Functions of the large intestine include the absorption of water and electrolytes and the elimination of feces. In the large intestine, mechanical digestion begins when chyme moves from the ileum into the cecum , an activity regulated by the ileocecal sphincter. Right after you eat, peristalsis in the ileum forces chyme into the cecum.
During digestion, the bonds between glucose molecules are broken by salivary and pancreatic amylase, and result in progressively smaller chains of glucose. This process produces the simple sugars glucose and maltose two glucose molecules that can be absorbed by the small intestine.
Do segmental and peristaltic movements differ? Asked by: Jermain Dickens. Is peristalsis chemical or mechanical digestion? What are the symptoms of peristalsis? Is feeling peristalsis normal? WHat are the two main functions of peristalsis?
What foods increase peristalsis? ISBN: Get Full Solutions. Problem 27 How do segmental and peristaltic movements differ? Step 3 of 3. Author: Elaine N. Marieb ISBN: Other solutions Name the organs of the alimentary canal andaccessory digestive orga View Full Material. People also purchased. A chemist wants to make 5.
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