Chapter 15-Digestion & Absorption of Food

StudyBlue printing of Chapter 15-Digestion & Absorption of Food html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; background: transparent; } body { line-height: 1; } blockquote, q { quotes: none; } blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; } /* remember to define focus styles! */ :focus { outline: 0; } /* remember to highlight inserts somehow! */ ins { text-decoration: none; } del { text-decoration: line-through; } /* tables still need 'cellspacing="0"' in the markup */ table { border-collapse: collapse; border-spacing: 0; } /* end RESET */ .header { min-width:800px; } .logo { padding:6px 20px 2px 20px; margin:0; font-size:25px; font-weight:bold; color:#808285; position:relative; border-bottom: 1px solid #c5c5c5; } .logo-blue { color:#70adc4; } .logo-desc { font-weight:normal; font-size:19px; color:#cccccc; margin-top:50px; position:absolute; display: none; } .back-button { position:absolute; top:20px; right:20px; font-size:13px; line-height:25px; color:rgb(0,175,225); font-weight:normal; } .back-button a { color:rgb(0,175,225); } .instructions { padding:0; margin:0; width:100%; position:relative; color:rgb(100,100,100); } .step-holder { border-left:1px solid #ededed; margin-left:20px; } .steps { padding:15px 0; float:left; width:24%; border-right:1px solid #ededed; text-align:center; } .steps-01 { } .steps-02 { } .steps-03 { } .steps-04 { } .label { padding:5px 10px; } .print-button { } .print-button a { background-color:rgb(0,175,225); color:white; line-height: 19px; padding:9px 8px 5px 30px; font-size:14px; text-decoration:none; background-image: url(images/printer.png); background-repeat: no-repeat; background-position: 7px 50%; -moz-border-radius: 5px; -webkit-border-radius: 5px; } .print-button a:hover { background-color:black; } .theNote .content { width: 8.0in !important; margin: 5px auto; padding:20px; background-color:white; } .theNote .header { border-bottom: 1px dashed #C8C8C8; font-size: 17px; padding: 0 0 10px; line-height: 19px; color: #00ADE1; min-width:500px; } .theNote .body { font-size: 14px; line-height: 19px; padding: 10px 0; } .theNote{ padding:6px 0; clear:both; background-color: rgb(200,200,200); } .theNote h3{ color: rgb(100,100,100); } .theNote h1, .theNote h3{ background-color:white; padding:2px 20px; width:8.0in !important; margin: 0 auto; font-size: 15px; } .theNote h1{ padding-top: 10px; font-size: 15px; } .theNote h1:first-child{ font-size: 20px; } .theNote h3 { font-size: 14px; font-weight: normal; } #options { border: 3px double #ccc; padding: 5px 12px; margin: 10px 50px 10px 20px; float: left; } #info { border-top: 1px solid #ccc; padding-top: 5px; font-style: italic; } li { margin: 5px 10px 5px 25px; } ul li { list-style: disc; } ol li { list-style: decimal; } img { border: 0; } table { clear: both; width: 100%; border: 1px solid #c5c5c5; border-width: 1px 0; margin: 0; page-break-after: always; } table#page { page-break-after: auto; } td { text-align: center; font-size: 12px; border-bottom: 1px dashed #c5c5c5; height: 1.75in; width: 50%; padding-left: 15px; } .leftside { border-right: 1px solid #cccccc; padding: 0 15px 0 0; } .bottom td { border-bottom: none; } .clearfix { clear:both; line-height:1px; height:1px; } img { max-width:80%; max-height:150px; margin:20px; } @media print {.header { display: none; } .content .header{ display:inherit; } table { border: 1px dashed #bbb; border-width: 1px 0; } .theNote{ background-color:white; } } Digestive System Anatomy major functions: motility digestion absorption secretion Structure of Gastrointestinal Wall increased surface area=increased absorption (Villi) Microvilli also increase surface area and form brush order Carbohydrates Most Carbohydrates in the diet are consumed as disaccharides or polysaccharides : sucrose lactose maltose starch glycogen cellulose Only momosaccharides are absorbed by the intestinal cells for use in the body Disaccharides and polysaccharides must be digested into monosaccharides before they can be absorbed for use in the body Carb Absorption & Digestion Summary of Liver Function Exocrine (Digestive functions) 1. synthesizes & secretes bile salts, which are necessary for adequate digestion & absorption of fats 2. Secretes into the bile a HCO3- rich solution that helps neutralize acid in the duodenum Endocrine Functions 1. In response to growth hormone, secretes insulin-like growth factor 1 (IGF-1), which promotes growth by stimulating cell division in various tissues, including bone 2. Contributes to the activation of vitamin D 3. Secretes angiotensinogen, which renin acts upin to form angiotensin 1 4. Metabolizes hormones 5. Secretes peptides & proteins involved in immune defenses Clotting Functions 1. Produces many of the plasma clotting factors, including prothrombin & fibrinogen 2. Produces bile salts, which are essential for the gastrointestinal absorption of vitamin K, which is, in turn, needed for the production of the clotting factors Plasma Proteins 1. Synthesizes & secretes plasma albumin, acute phase proteins, binding proteins for various hormones and trace elements, lipoproteins, and other proteins mentioned elsewhere in this table Organic Metabolism 1. Converts plasma glucose into glycogen & triglycerides duting absorptive period 2. Converts plasma amino acids to fatty acids, which can be incorporated into triglycerides during absorptive period 3. Synthesizes triglycerides & secretes them as lipoproteins during absorptive period 4. Produces glucoes from glycogen (glycogenolysis) and other sources (gluconcogenesis) during postabsorptive period & release glucose into the blood 5. Converts fatty acids into ketones during fasting 6. Produces urea, the major end product of amino acid (protein) catabolism, and releases it into the blood Cholesterol Metabolism 1. Synthesizes cholesterol & releases it into the blood 2. Secretes plasma cholesterol into the bile 3. Converts plasma cholesterol into bile salts Excretory & degradative functions 1. Secretes bilirubin & other bile pigments into the bile 2. Excretes, via the bile, many endogenous & foreign organic molecules as well as trace metals 3. Biotransforms many endogenous & foreign organic molecules 4. Destroys old erythrocytes Proteins Proteins are broken down to peptide fragments in the stomach by pepsin, and in the small intestine by trypsin and chymotrypsin, the major preteases secreted by the pancreas these fragments are further digested to free amino acids by carboxypeptidase from the pancreas & aminopeptidase, located on the luminal membranes of the small intestine epithelial cells the free amino acids then enter the epithelial cells by secondary active transport coupled to Na+ Short chains or two or three amino acids are also absorbed by a secondary active transport coupled to the hydrogen ion gradient Protein Digestion & Absorption