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13 The Digestive System and Nutrition Lesson 13.1: Nutrition Lesson 13.2: Anatomy and Physiology of the Digestive System Lesson 13.3: Disorders and Diseases of the Digestive System Chapter 13: The Digestive System and Nutrition Lesson 13.1 Nutrition Nutrition • Energy – The ability of physical systems to do work • • • • Heat Chemical Kinetic Potential – Metabolism = the sum of all chemical & physical activities in an organism. © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Energy • measuring the body’s energy use – Calorie (used to measure food’s potential energy) – Kilocalories (kcal) • Calorie is the unit used to measure the potential energy in foods • The amount of heat required to raise the temperature of 1 kcal of water by 1°C • basal metabolic rate (BMR) – energy required for one day at rest – varies by individual © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Macronutrients, Vitamins, and Minerals • nutrients – substances needed for • energy • growth • maintenance • Water is a nutrient. Tischenko Irina/Shutterstock.com © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Nutrients • Macronutrients – carbohydrates – proteins – fats (lipids) • Essential Nutrients (micronutrients) – vitamins – minerals © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Nutrients • Essential Nutrients – Vitamins • Organic chemicals needed by the body for normal functioning & good health • Certain health problems occur without them – Minerals • Elements that the body needs in relatively small amounts © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Carbohydrates • Sugars (fruit, table sugar, sodas) • Starches (bread, pasta, cereal) • 1 gram supplies 4 Calories • 50% of daily caloric intake should be from carbohydrates – No more than 25% should come from sugar • (such as in candy & sodas) © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Proteins • made of amino acids • essential amino acids – must be part of diet • nonessential amino acids – body can make • one gram supplies 4 Calories • 25% of daily caloric intake from proteins • Meats (vegetarians eat beans, peas, or soy) © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Fats • Lipids (includes oils & solid fat) • saturated fats (most solid at room temp.) – Most come from animals (meat & dairy) – Some oils (coconut & palm oil) • unsatuated fats (most come from plants) • 3 types – monounsaturated fats – polyunsaturated fats – trans-unsaturated fats (trans fats) © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Unsaturated Fats • monounsaturated fats (liquid) – Canola & Olive oils • polyunsaturated fats (liquid) – Corn & Soybean oils • trans-unsaturated fats (trans fats) – artificially produced – Solid at room temp © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Fats • one gram supplies 9 Calories • less than 25–35% of total calories from fat • minimize trans and saturated fat intake – Especially bad for cardiovascular health • Everyone is recommended to restrict fats in your diet. © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Vitamins • Only small amounts are needed for proper metabolism • types of vitamins – fat-soluble • may be stored in the body’s fat • Aren’t easily excreted so they can be toxic – water-soluble • are not stored in the body • Excess is expelled with urine • Most are COENZYMES – combines with protein to make a working enzyme • vitamin deficiency- long term lack of a particular vitamin (usually causes disease) © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Water-Soluble Vitamins © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Fat-Soluble Vitamins © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Minerals • elements needed for proper body function • examples – – – – calcium potassium iron phosphorus © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Minerals © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Chapter 13: The Digestive System and Nutrition Lesson 13.2 Anatomy and Physiology of the Digestive System Activities of Digestion • (1) ingestion – getting food into the body • (2) propulsion – moving food along GI tract • a) swallowing • b) peristalsis • c) mass movements © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Activities of Digestion • (3) mechanical breakdown – breaks food into smaller pieces – increases surface area of food • a) chewing w/teeth & tongue • b) churning of stomach • c) segmentation of intestines © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Activities of Digestion • (4) chemical breakdown –also known as digestion –enzymes • Mouth – salivary amylase • Stomach – pepsin, gastrin & HCl • Small Intestine – pancreatic amylase, nuclease, lipase & trypsin © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Activities of Digestion • (5) absorption –digested food particles moved into blood • (6) defecation –Release of indigestible remains & dead bacteria bodies © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Activities of Digestion © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Layers of the Alimentary Canal (GI tract) • Mucosa (mucus membranes) – innermost layer – epithelial cells – adjacent to lumen – often secretes mucus • Submucosa – below mucosa – Lymphatic tissue & glands secrete substances that aid in digestion & absoption © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Layers of the Alimentary Canal • muscularis externa (causes peristalsis) – circular muscle – longitudinal muscle • serosa (serous membrane) – outermost layer – peritoneum • visceral • parietal • Mesentery – Holds abdominopelvic organs in place (especially Sm. Int.) © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Digestive Organs and Their Functions • • • • • • the oral cavity the nasal cavity teeth and gums salivary glands pharynx esophagus © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Digestive Organs and Their Functions • • • • • • • • stomach small intestine liver and gallbladder pancreas large intestine rectum anal canal anus © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. The Oral Cavity • • • • lips tongue cheeks palate – hard – Soft • Ingestion, chemical & physical digestion, and propulsion © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. The Nasal Cavity • passageway for air (while you chew) • uvula – hangs from soft palate – keeps food out of nasal cavity when swallowing © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Teeth and Gums • gum – gingiva • teeth – deciduous – permanent • incisor • canine • molar © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Salivary Glands • parotid • submandibular • Sublingual • saliva – Water, enzymes, mucus & antibodies • Moistens & lubricates food, protects against bacteria, and starts chemical digestion © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Pharynx • Nasopharynx – Only air • Oropharynx – Food & air • laryngopharynx – Glottis • Opening for larynx – epiglottis © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Esophagus • connects pharynx to stomach • peristalsis – muscle contraction changes size of tube – food is moved through GI tract © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Stomach • regions – – – – cardia fundus body pyloric region • three layers of muscle © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Lining of the Stomach • gastric gland – mucus-secreting cells – parietal cells • Secrete HCl – chief cells • Produce pepsin – enteroendocrine cells • Produce gastrin © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Chemical Reactions in the Stomach • protein-digesting enzymes secreted • chyme formation – Acidic gastric juices mixed w/food • stomach contractions – Rugae flatten to allow more volume – 3 muscle types churn © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Small Intestine • segments – duodenum – jejunum – Ileum • 6-8 yards long © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Small Intestine • lining – villi – intestinal crypts (similar to gastric pits in stomach) © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Small Intestine • chemical breakdown – Fat emulsification by bile – break down by nuclease • absorption into the blood – from capillaries to the blood – lacteal to lymph – vitamin B12 © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. The Liver • functions of the liver – – – – maintains nutrients in blood converts one nutrient to another stores nutrients inactivates toxins • hepatic portal vein – Deoxygenated blood is diverted • parts of the liver – – – – – lobules hepatocytes blood vessels bile canaliculi bile salts © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. The Gallbladder • functions of the gallbladder – stores bile produced by liver – releases bile when fat-containing chyme is in duodenum – Chemically breaks down fat © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Pancreas • pancreatic juices – contain digestive enzymes • Amylase, nuclease, lipase, trypsin • Released into duodenum • glucose regulation – beta cells–insulin • Lowers blood glucose levels – alpha cells–glucagon • When glucagon reaches it, the liver then breaks down stored glycogen into glucose, which is released into blood © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Large Intestine • regions – Cecum (w/appendix) – colon • • • • ascending transverse descending Sigmoid 5’ long – larger diam. Absorption: – water, electrolytes – vitamin K – Mass movements © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Rectum, Anal Canal, and Anus • rectum • anal canal • anus – sphincters • internal • External © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Chapter 13: The Digestive System and Nutrition Lesson 13.3 Disorders and Diseases of the Digestive System Disorders and Diseases of the Digestive System • gingivitis and periodontal disease – plaque forms tarter • cardiovascular disease • gastroesophageal reflux disease (GERD) – heartburn © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Disorders and Diseases of the Digestive System • Ulcers – Stomach or duodenum – Helicobacter pylori • gastroenteritis – inflammation of stomach or intestine © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Disorders and Diseases of the Digestive System • inflammatory bowel disease – chronic inflammation – ulcerative colitis – Crohn’s disease • constipation and diarrhea – infrequent or too frequent defecation © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Disorders and Diseases of the Digestive System • hepatitis – inflammation of liver • pancreatitis – inflammation of pancreas © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only. Disorders and Diseases of the Digestive System • gallstones – bile forms crystals – Cholecystectomy • cancer – digestive system cancers are common © Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only.