Chapter 23 study guide PDF

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fall is the last time to take this class before they combine anatomy and physiology...

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Chapter 23: The Digestive System What are the structures of the alimentary canal in the proper sequence from mouth to anus? 1. 2. 3. 4. 5.

Pharynx Esophagus Stomach Small intestine Large intestine

What are the accessory organs of the digestive system? Aids in the breakdown of food  Salivary glands  Liver  Gall bladder  Pancreas What are the four basic tissue layers of the wall of the alimentary canal? What types of tissues are found within each? 1. 2. 3. 4.

Mucosa  epithelial Submucosa  dense connective Muscularis  smooth muscle Serosa  loose connective

How do chemical and mechanical digestion differ? Chemical digestion: enzymatic breakdown of food Mechanical digestion: chewing, mixing, and segmentation that prepares food for chemical digestion What are the functions of saliva? What enzymes are present in saliva? What are the functions of lysozymes? Saliva: aqueous solution of proteins and ions secreted into the mouth by the salivary glands Enzyme: salivary amylase Lysozymes: filled with enzymes that help the cell to digest large molecules, as well as old cell parts and foreign particles, such as bacteria What two structures are important in containment of the bolus within the pharynx as it moves toward the esophagus? 1. epiglottis 2. upper esophageal sphincter What tissue type lines the esophagus? Stratified squamous epithelium

What is peristalsis?

Muscular contraction and relaxations that propel food through the GI tract What is different about the Muscularis of the stomach from other sections of the GI tract? Muscularis: muscle (skeletal or smooth) layer of the alimentary canal wall 

In the small intestine = made up of double layer of smooth muscle

What do parietal cells, chief cells, and G cells of the gastric glands secrete and what is the function of each secretion? Parietal cell: gastric gland cell that secretes hydrochloric acid and intrinsic factor  protects vitamin B12 from acidic stomach environment Chief cell: gastric gland cell that secretes pepsinogen  acid environment of the stomach pepsinogen is converted into the active enzyme pepsin which digests large proteins into smaller polypeptide chains G cell: gastrin- secreting/ hormone that stimulates the release of HCL and stimulates gastric mobility  secretion is stimulated by the presence of peptides, amino acids and calcium What is a zymogen? What is the zymogen of pepsin? What are the substrate and products of pepsin action? Zymogen: an inactive substance that is converted into an enzyme when activated by another enzyme Zymogen pepsin: Enzymes like pepsin are created in the form of pepsinogen, an inactive zymogen. Pepsinogen is activated when chief cells release it into the gastric acid, whose hydrochloric acid partially activates it

What do mucus cells secrete that is important for protecting the stomach lining? Gastric enzymes What structure controls movement of chyme from the stomach to the small intestine? Lower esophageal sphincter  segmentation What are the three sections of the small intestine? Where do most enzymes enter? 1. Duodenum  pyloric sphincter – jejunum 2. Jejunum  duodenum – ileum 3. Ileum  jejunum – large intestine What structural modifications vastly increase the absorptive surface area of the small intestine? Villi What is segmentation? Separates chime and then pushes it back together, mixing it and providing time for digestion and absorption

Where does chyme enter the large intestine? What are the sections of the large intestine called in the correct sequence? Chyme: ileocecal valve 1. Cecum 2. Colon 3. Rectum 4. Anus Where does most water reabsorption occur in the GI tract? Small intestine What important vitamin do we receive from the action of the gut flora of the large intestine?   

Biotin Pantothenic acid vitamin K

In what section of the small intestine do bile and pancreatic secretions enter? bile: (alkaline solution) mixture secreted by the liver and important for the emulsification of lipids pancreatic: pancreas produces pancreatic juices which contain digestive enzymes and bicarbonate ions, and delivers it to the duodenum What are the functions of the liver? What important secretion is synthesized in the liver, stored in the gall bladder before release into the small intestine? What is its function? Liver: largest gland in the body whose main digestive function is the production of bile  

hepatic artery/ hepatic portal vein synthesis of plasma proteins such as fats, proteins, and carbohydrates in portal blood

Gallbladder: accessory digestive organ that stores and concentrates bile 

cystic duct

What digestive enzymes – active or inactive (trypsinogen, chymotrypsinogen, elastase, carboxypeptidase, pancreatic lipase, nucleases and pancreatic amylase) are secreted by the pancreas and what is the substrate of each? trypsinogen: chymotrypsinogen: elastase: carboxypeptidase: pancreatic lipase: nucleases: pancreatic amylase: How are carbohydrates broken down and absorbed on their journey through the GI tract?

What enzymes are involved and what is their role in protein digestion in the GI tract prior to absorption?

How is fat broken down and absorbed in the GI tract? What role do bile and pancreatic lipase play? Chapter 24 Metabolism and Nutrition – (cellular respiration etc.) no questions from this chapter...