Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Digestive System and Nutrition
Document related concepts
Transcript
Digestive System and Nutrition Organs Process of Digestion Nutrition Path of Food through the Digestive System mouth pharynx esophagus Produces peptidases, maltase, lactase Produces pepsin, HCl stomach small intestine large intestine anal canal Peristalsis: Muscular contractions that move food through the digestive system Accessory Organs and Glands Produce salivary amylase salivary glands Produces bile Produces pancreatic amylase, trypsin, lipase liver gall bladder Stores bile pancreas Process of Digestion and Absorption • Mouth – Teeth chew food into smaller pieces – Salivary amylase (enzyme in saliva) begins starch digestion – Tongue mixes food with saliva to form Starch in bun has been broken into bolus to be smaller chains of swallowed sugars Process of Digestion and Absorption • Stomach – HCl acid unfolds proteins – Pepsin (enzyme) begins protein digestion, breaking some peptide bonds esophagus sphincter muscularis layer has three layers of muscle pyloric sphincter mucosa layer has rugae gastric pit gastric gland Protein in beef has been broken into smaller chains of amino acids cells that secrete gastric juice Contains pepsin, HCl, mucus Process of Digestion and Absorption • Small Intestine villus – Large surface area due to numerous villi – Bile emulsifies lipids – Pancreatic and intestinal enzymes digest carbohydrates, lipids, venule proteins – Amino acids and sugars arteriole lymphatic absorbed into blood vessel – Lipids absorbed into Carbohydrate, Protein and Fat lymphatic system have been digested and absorbed lacteal blood capillaries Digestion occurs by Hydrolysis of Macromolecules Emulsification: physical dispersion of lipids into smaller droplets carbohydrate pancreatic amylase Hydrolysis: chemical separation of subunits maltase cell of intestinal villus protein + bile salts fat globules trypsin emulsification droplets peptides hydrolysis peptidase lipase Hydrolysis glucose amino acids pH = basic pH = basic pH = basic blood capillary Carbohydrate digestion blood capillary Protein digestion lymphatic capillary Fat digestion Process of Digestion and Absorption • Large Intestine – Absorbs water – Absorbs salts (minerals) – Absorbs some vitamins – Stores waste for later elimination Calcium from cheese has been absorbed. Fiber from tomatoes and lettuce remains. Distribution and Use of Nutrients • Liver – regulates nutrient entry into blood – detoxifies blood – stores iron and fat-soluble vitamins – makes plasma proteins – stores and releases glucose – produces urea from amino acids – produces bile – destroys old red blood cells – helps regulate blood cholesterol Applying Your Knowledge 1. 2. 3. 4. A. B. C. D. Stomach Mouth Large Intestine Small Intestine Where are fats digested? Where do proteins unfold? Where does starch digestion begin? Where is water absorbed? Nutritional Recommendations • Macronutrients – Carbohydrate – Fat – Protein • Water • Micronutrients – Vitamins – Minerals Use fats in small amounts June 2011 Recommendations Balancing Calories • Enjoy your food, but eat less. • Avoid oversized portions. Foods to Increase • Make half your plate fruits and vegetables. • Make at least half your grains whole grains. • Switch to fat-free or low-fat (1%) milk. Foods to Reduce • Compare sodium in foods like soup, bread, and frozen meals, and choose the foods with lower numbers. • Drink water instead of sugary drinks. Carbohydrates: Dietary Recommendations • 58% of calories from carbohydrates • No more than 10% of calories from simple, refined sugars • Emphasize – Complex Carbohydrates • Starch • Fiber (cellulose) – Naturally-occurring simple carbohydrates • Fructose from fruit • Lactose from milk Fats: Dietary Recommendations • • • • < 30% of calories from fats < 10% of calories from saturated fats Limit cholesterol to 300 mg/day Avoid “trans” fatty acids in partially hydrogenated products • Emphasize – Unsaturated fatty acids from vegetables, fish, legumes, and nuts – Oils: mono- or polyunsaturated Proteins: Dietary Recommendations • 12% of calories from proteins • 8 essential amino acids obtained from –Lean sources of animal protein –Complementary plant proteins • Beans + Grains • Beans + Seeds Vitamins • Organic compounds used in metabolic reactions as coenzymes or antioxidants • Water Soluble: B vitamins, C • Fat Soluble: A, D, E, K • Adequate amounts come from a varied diet that includes vegetables and fruits • May prevent cancer and cardiovascular disease Minerals • Inorganic substances required by the body • Macrominerals needed in large amounts, eg. calcium • Microminerals needed in smaller amounts, eg. iron • May need to emphasize certain foods to obtain iron or calcium • May need to limit foods high in sodium Applying Your Knowledge 1. 2. 3. 4. 5. Calcium Vitamin C Lipid Carbohydrate Protein A. Which one is a mineral? B. Which macronutrient should supply the greatest number of calories in the diet? C. Which one may protect against cancer? Reading a Nutrition Label More info at http://www.fda.gov Calorie Percentage Calculations Number of grams Caloric value 12 x 9/250 = 0.432 x 100 = 43.2% 3 x 9/250 = 0.108 x 100 = 10.8% 31 x 4/250 = 0.496 x 100 = 49.6% 5 x 4/250 = 0.080 x 100 = 8.0% 5 x 4/250 = 0.080 x 100 = 8.0% These should add to 100%. Total calories
