Search for:. 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.
Segmentation, also called metamerism, or metameric segmentation, in zoology, the condition of being constructed of a linear series of repeating parts, each being a metamere body segment, or somite and each being formed in sequence in the embryo, from anterior to posterior.
Skip to content Technology. May 7, Joe Ford. Table of Contents. In general, it mainly occurs in the small intestine. However, these localized contractions are responsible for the back and forth movement of food. It allows the continuous subdivision, breaking up, and mixing the contents. Therefore, segmentation facilitates the mixing of food with the secretions of the small intestine while allowing mechanical digestion.
Thus, it both facilitates absorption of nutrients through digestion as well as the propagation of food towards the end of the gastrointestinal tract slowly. Figure 2: Digestive Process.
Peristalsis refers to the involuntary contraction and relaxation of muscles of the intestine, creating wave-like movements, pushing the contents of the canal forward while segmentation refers to the back and forth smooth muscle contractions mainly in the small intestine for the smooth muscle contractions. While peristalsis mainly occurs in the esophagus, segmentation mainly occurs in the small and large intestine. Peristalsis occurs by the contractions of the circular muscles while segmentation occurs due to the rhythmic contractions of the longitudinal muscles.
Peristalsis occurs when the circular and longitudinal muscles of the GI tract contract and relax with an alternate manner. Segmentation occurs when the circular muscle contracts in front and backward directions.
This is the difference between peristalsis and segmentation. Available here 2. Available here. Jun 19, Samanthi Udayangani holds a B. Degree in Plant Science, M. Your email address will not be published. Figure Peristalsis. Figure Segmentation. Leave a Reply Cancel reply Your email address will not be published. Peristalsis vs Segmentation. The wave-like rhythmic muscular contractions of the GI tract that propel food downward is known as peristalsis.
Segmentation is a muscular type movement of the intestine.
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