Digestion, Absorption & Metabolism of Nutrients

[Audio] Digestion, Absorption & Metabolism of Nutrients.

[Audio] Nutrients are compounds in foods Essential to life and health, providing us with energy Building blocks for repair and growth Substances necessary to regulate chemical processes Six major nutrients: Carbohydrates Lipids Proteins Vitamins Minerals Water Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures,-hair, scales, feathers, or exoskeletons Digestion: Is the process, breakdown of the ingested food into absorbable molecules. Absorption: The movement of nutrients, water and electrolytes from the lumen of the small intestine into the cell, then into the blood utrients are compounds in foods Essential to life and health, providing us with energy Building blocks for repair and growth Substances necessary to regulate chemical processes Six major nutrients: Carbohydrates Lipids Proteins Vitamins Minerals Water Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures,-hair, scales, feathers, or exoskeletons Digestion: Is the process, breakdown of the ingested food into absorbable molecules. Absorption: The movement of nutrients, water and electrolytes from the lumen of the small intestine into the cell, then into the blood.

[Audio] Metabolism: All chemical reactions involved in maintaining the living state of the cells and the organism Two categories 1. Catabolism - Breakdown of molecules to obtain energy 2. Anabolism - Synthesis of all compounds needed by the cells Carbohydrates Is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms Saccharide: A group that includes sugars, starch, and cellulose. Four chemical groups: 1. Monosaccharides (sugars): Low molecular weight-Glucose, galactose, fructose 2. Disaccharides: Sucrose, lactose, maltose, trehalose 3. Polysaccharides: Starch, Glycogen, Cellulose, Hemicellulose, Pectins 4. Oligosaccharides: Maltodextrins, Raffinose, stachyose The Fate of Glucose : Because glucose is the body’s preferred source for synthesizing ATP, its use depends on the needs of body cells ATP production Amino acid synthesis Glycogen synthesis Triglyceride synthesis Metabolism: All chemical reactions involved in maintaining the living state of the cells and the organism Two categories 1. Catabolism - Breakdown of molecules to obtain energy 2. Anabolism - Synthesis of all compounds needed by the cells.

[Audio] Digestion of carbohydrates. [image] Area Mouth Stomach Small intestine Juice Saliva Gastric juice Pancreatic juice Succus entericus Enzyme Salivary amylase Gastric amylase Pancreatic amylase Sucrase Maltase Lactase Dextrinase Trehalase Substrate Polysaccharides - cooked starch Weak amylase Polysaccharides Sucrose Maltose and maltriose Lactose Dextrin, maltose and maltriose Trehalose End product Disaccharides - dextrin and maltose The action is negligible Disaccharides - Dextrin, maltose and maltrose Glucose and fructose Glucose Glucose and galactose Glucose Glucose.

[Audio] ABSORPTION OF GLUCOSE Glucose is transported from the lumen of small intestine into the epithelial cells in the mucus membrane of small intestine, by means of sodium cotransport. Energy for this is obtained by the binding process of sodium ion and glucose molecule to carrier protein. From the epithelial cell, glucose is absorbed into the portal vein by facilitated diffusion. Sodium ion moves laterally into the intercellular space. It is transported into blood by active transport, utilizing the energy liberated by breakdown of ATP. ABSORPTION OF GALACTOSE Galactose is also absorbed from the small intestine in the same mechanism as that of glucose. „ ABSORPTION OF FRUCTOSE Fructose is absorbed into blood by means of facilitated diffusion. Some molecules of fructose are converted into glucose ABSORPTION OF GLUCOSE Glucose is transported from the lumen of small intestine into the epithelial cells in the mucus membrane of small intestine, by means of sodium cotransport. Energy for this is obtained by the binding process of sodium ion and glucose molecule to carrier protein. From the epithelial cell, glucose is absorbed into the portal vein by facilitated diffusion. Sodium ion moves laterally into the intercellular space. It is transported into blood by active transport, utilizing the energy liberated by breakdown of ATP. ABSORPTION OF GALACTOSE Galactose is also absorbed from the small intestine in the same mechanism as that of glucose. „ ABSORPTION OF FRUCTOSE Fructose is absorbed into blood by means of facilitated diffusion. Some molecules of fructose are converted into glucose.

[Audio] Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Digestion and absorption • A* Biology Glucose transport.

[Audio] Glucose Catabolism. Glucose Catabolism.

[Audio] Carbohydrate metabolism. [image] Through hepatic portal vein Glucose Liver Glycogen Amino acid Triglycerides Tissues other than muscle Glucose Oxidation Energy + H20 + C02 Absorption Of glucose from small intestine Glucose Systemic circulation Lactic acid Glucose H20 Muscle Glucose Stored glycogen Glucose utilized Pyruvic acid Anaerobic Lactic acid C02 + H20 Lungs CO removed b Aerobi c Acetyl COA 1 Krebs cycle Energy expired air.

[Audio] PROTEINS Is a macronutrient Found in animal products, nuts and legumes. Is composed of amino acids Proteins are polymer chains made of amino acids linked together by peptide bonds. Proteins are broken down in the stomach to smaller polypeptide chains via hydrochloric acid and protease actions Amino acids are the building blocks of proteins Proteins are the building blocks of muscle mass, “When protein is broken down in the body it helps to fuel muscle mass, which helps metabolism Wheat: Glutenin and gliadin, which constitute gluten 2. Milk: Casein, lactalbumin, albumin and myosin 3. Egg: Albumin and vitellin 4. Meat: Collagen, albumin & myosin..

[Audio] Amino acids are organic compounds that contain amine (–NH2) and carboxyl (–COOH) functional groups, along with a side chain (R group) specific to each amino acid. Three types 1. Essential amino acid: Cannot be by the organism- must be supplied in its diet 2. Conditionally essential: Synthesis can be limited under special pathophysiological conditions 3. Non- essential amino acid: Can be synthesized in sufficient quantities in the body..

[Audio] DIGESTION OF PROTEINS ABSORPTION OF PROTEINS Proteins are absorbed in the form of amino acids from small intestine. The levo amino acids are actively absorbed by means of sodium cotranspor The dextro amino acids are absorbed by means of facilitated diffusion. Absorption of amino acids is faster in duodenum and jejunum and slower in ileum..

[Audio] Protein metabolism. Protein metabolism.

[Audio] Lipids (Fats) Lipids are molecules that contain hydrocarbons Make up the building blocks of the structure and function of living cells. Examples Fats, oils, waxes, vitamins (such as A, D, E and K), hormones Most of the cell membrane that is not made up of protein Functions Storing energy, signaling, and acting as structural components of cell membranes Applications Cosmetic and food industries as well as in nanotechnology Lipid is sometimes used as a synonym for fats Fats are a subgroup of lipids called triglycerides Usual diet also contains small quantities of cholesterol and cholesterol esters Dietary fats are classified into two types: 1. Saturated fats 2. Unsaturated fats.

[Audio] SATURATED FATS Saturated fats are the fats which contain triglycerides formed from only saturated fatty acids The fatty acids having maximum amount of hydrogen ions without any double bonds between carbon atoms are called saturated fatty acids. „UNSATURATED FATS Fats containing unsaturated fatty acids are known as unsaturated fats. Unsaturated fatty acids are fatty acids formed by dehydrogenation of saturated fatty acids. Three types: 1. Monounsaturated fats 2. Polyunsaturated fats 3. Trans fats 1. Monounsaturated Fats: Contain one double bond between the carbon atoms 2. Polyunsaturated Fats: Unsaturated fats with more than one double bond between the carbon atoms- essential fatty acids Polyunsaturated fats are of two types: Omega-3 - omega3 fatty acids having double bond in the third space from the end of the carbon chain Omega-6 - omega6 fatty acids having double bond in the sixth space from the end of the carbon chain. 3. Trans Fats Trans fats or trans fatty acids are unsaturated fatty acids, with molecules containing trans (across or opposite side) double bonds between carbon atoms..

[Audio] Sources and functions of dietary fats. [image] u Saturated fats Monounsaturated fats Polyunsaturated fats Trans fats ources Full fat milk, cheese, cream, butter Commercially baked biscuits and pastries Deep-fried fast food Coconut oil and palm oil Fatty meat Oils (canola, olive and peanut oils) Nuts (cashews, almonds, hazelnuts and peanuts) Margarine Fruits and vegetables Vegetable oils (sunflower, safflower, corn or soy oils) Nuts (walnuts) Flax seeds Polyunsaturated margarines Lean meat Fish and sea foods Egg Milk Cheese and table margarines Lamb and beef on Increase blood cholesterol and thereby increase the risk of atherosclerosis and coronary healt diseases Decrease blood cholesterol and thereby decrease the risk of coronary heart diseases Decrease Blood cholesterol and triglycerides and thereby reduces blood pressure Risk of coronary heart diseases Risk of obesity Platelet aggregation and prevents excess blood clotting Inflammation throughout body Increase Disease-countering actions in the body Increase low density lipoproteins and thereby increase the risk of atherosclerosis and coronary healt diseases.

[Audio] Fat digestion. Fat digestion. [image] Area Mouth Stomach Small intestine Juice Saliva Gastric juice Pancreatic juice Succus entericus Enzyme Lingual lipase Gastric lipase (weak lipase) Pancreatic lipase Cholesterol ester hydrolase Phospholipase A Phospholipase B Colipase Bile-salt-activated lipase Intestinal lipase Substrate Triglycerides Triglycerides Triglycerides Cholesterol ester Phospholipids Lysophospholipids Facilitates action of pancreatic lipase Phospholipids Cholesterol esters Triglycerides End product Fatty acid 1, 2-diacylglycerol Fatty acids Glycerol Monoglycerides Fatty acid Free cholesterol Fatty acid Lysophospholipids Phosphoryl choline Free fatty acids Lysophospholipids Cholesterol and fatty acids Fatty acids Glycerol (weak action).

[Audio] ABSORPTION OF LIPIDS Monoglycerides, cholesterol and fatty acids from the micelles enter the cells of intestinal mucosa by simple diffusion. From here, further transport occurs as follows: In the mucosal cells, most of the monoglycerides are converted into triglycerides. Triglycerides are also formed by re-esterification of fatty acids with more than 10 to 12 carbon atoms. Some of the cholesterol is also esterified. Triglycerides and cholesterol esters are coated with a layer of protein, cholesterol and phospholipids to form the particles called chylomicrons. Chylomicrons cannot pass through the membrane of the blood capillaries because of the larger size. These lipid particles enter the lymph vessels and then are transferred into blood from lymph. 2. Fatty acids containing less than 10 to 12 carbon atoms enter the portal blood from mucosal cells and are transported as free fatty acids or unesterified fatty acids. Most of the fats are absorbed in the upper part of small intestine. Presence of bile is essential for fat absorption..

[Audio] Fats metabolism. [image] Ttvough tæpatic Fxxtal vein Liver Tr igtycerides Fatty acids Acetyl COA Krebs cycle Ketone bodies H20 Kidney Ketone bodies thrCRJgh Absorption Of from small intestine S y sternic circulation Triglycerides Triglycerides Ketone bodies 02 C02 Fat depot Glycerol Utilization Ketone bod ies Krebs cycl o C02+ H20 • ATP C02 removed by air.

[Audio] Metabolic pathways during the absorptive state.

[Audio] Metabolic pathways during the post-absorptive state..

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