BIOL 232 Biology II Lecture Animal Nutrition PDF

BIOL 232 BIOLOGY II II Digestive Systems & Nutrition...

BIOL 232 BIOLOGY II II Digestive Systems & Nutrition 3 Session 1: Animal and Human Part Outlines  Presented By: Dr. Noura Abou Zeinab  Digestive Tracts  Incomplete versus Complete Tracts  Continuous versus Discontinuous Feeders Dentition Among Mammals  Email: [email protected]   Human Digestive Tract (system)  Mouth  Stomach  Small Intestine  Large Intestine  Accessory Organs  Digestive Enzymes  Nutrition and Human Health 2 4  DIGESTIVE TRACTS INCOMPLETE DIGESTIVE TRACT OF A PLANARIAN 5 DIGESTIVE TRACTS COMPLETE DIGESTIVE TRACT OF AN EARTHWORM Incomplete versus Complete Tracts  Incomplete tract: has a single opening  Ex: Planarian  Food enters through mouth and muscular pharynx  Gastrovascular cavity branches throughout the body  Wastes exit through mouth and muscular pharynx  Lacks specialized parts  Complete Tract: has two openings  Ex: Earthworm  Food enters through mouth  Wastes exit through anus  Specialized of parts is obvious 6 COMPLETE DIGESTIVE TRACT OF AN EARTHWORM NUTRITIONAL MODE OF A CLAM COMPARED TO A SQUID 9 CONTINUOUS VERSUS DISCONTINUOUS FEEDERS ADAPTATIONS TO DIET  Continuous filter feeders  Dentition differs with mode of nutrition  Ex: Clams  Omnivores  Always have water moving into the mantle cavity via incurrent siphon  Variety of specializations  Particles deposited on gills  Accommodate both vegetation and meat  Do not need food storage area  Herbivores  Discontinuous feeders  Incisors for clipping  Ex: Squid  Premolars and molars for grinding  Uses tentacles to seize prey  Carnivores  Allows the beaklike jaws to pull pieces into the mouth  Pointed incisors and enlarged canines with the radula  Shear off pieces small enough to swallow  Food storage area needed 12 DENTITION AMONG MAMMALS THE HUMAN DIGESTIVE TRACT 13 15 HUMAN DIGESTIVE TRACT HUMAN DIGESTIVE TRACT  Humans digestive tract is complete Mouth  Part of a tube-within-a-tube body plan  Begins with a mouth and ends in an anus  Three major pairs of salivary glands  Saliva contains salivary amylase  Salivary amylase initiates starch digestion  Digestion entirely extracellular  Digestive enzymes are secreted by  Tongue is composed of striated muscle  The wall of the digestive tract, or  Mixes chewed food with saliva  By nearby glands  Forms mixture into bolus 14 16  PHARYNX AND ESOPHAGUS PERISTALSIS IN THE DIGESTIVE TRACT Pharynx  Where digestive and respiratory passages come together  Soft palate closes off nasopharynx  Epiglottis  Covers opening into trachea  Keeps food from air passages (most of the time) Esophagus  Takes food to stomach by peristalsis  Peristalsis - Rhythmical contraction to move contents in tubular organs 17 19 SWALLOWING Stomach Stomach  Stomach wall has deep folds  Folds disappear as the stomach fills to an approximate volume of one liter  Epithelial lining of the stomach has millions of gastric pits, which drain gastric glands  Gastric gland secretes hydrochloric acid and pepsin  Pepsin is a hydrolytic enzyme that acts on protein to produce peptides 18 20 ANATOMY OF THE STOMACH SMALL INTESTINE  First segment is duodenum Chyme from stomach enters the duodenum  Mixes with secretions from the liver and pancreas Liver  Produces bile, which is stored in gallbladder  Bile contains bile salts which break up fat into fat droplets via emulsification  Helps maintain glucose concentration in blood by converting excess into glycogen 21 23 Stomach  Food mixing with gastric juices becomes chyme  Junction between stomach and small intestine controlled by a sphincter  When the sphincter relaxes, a small quantity of chyme passes into the small intestine 22  SMALL INTESTINE ANATOMY OF THE SMALL INTESTINE Pancreas  Exocrine gland  Produces pancreatic juice and digestive enzymes into the duodenum  Pancreatic amylase digests starch to maltose  Trypsin digests protein to peptides  Lipase digests fat droplets to glycerol and fatty acids Epithelial cells intestine also produce enzymes  These complete digestion of peptides and sugars 25 27 ABSORPTION BY VILLI LARGE INTESTINE  Mucous membrane of small intestine  Includes cecum, colon, rectum, and anal  Has ridges and furrows that give it a canal corrugated surface  Larger in diameter, but shorter in length than small intestine  Villi are ridges on the surface, which contain  Absorbs water, salts, and some vitamins even smaller ridges, microvilli  Cecum has small projection - appendix  Greatly increase absorptive area  Colon subdivided into ascending, transverse,  Each villus contains blood capillaries and a descending, and sigmoid colon lymphatic capillary (lacteal)  Opening to anal canal - Anus 26 28 JUNCTION OF THE SMALL INTESTINE AND THE LARGE INTESTINE HUMAN DIGESTIVE TRACT 29 31 HUMAN DIGESTIVE TRACT HUMAN DIGESTIVE TRACT 30 32 HUMAN DIGESTIVE TRACT Liver; Gallbladder; and Pancreas 33 35 HUMAN DIGESTIVE TRACT DIGESTIVE ENZYMES 34 36  DIGESTIVE ENZYMES Nutrition and Human Health  Carbohydrates: are present in food in the form of sugars, starch, and fiber.  Fruits, vegetables, milk, and honey are natural sources of sugars.  Monosaccharides:  Glucose  Fructose  Disaccharides:  Lactose (milk sugar)  Sucrose (table sugar) 37 39 DIGESTION AND ABSORPTION OF NUTRIENTS Carbohydrate  After being absorbed from the digestive tract all sugars are converted to glucose  Glucose is the preferred direct energy source in cells.  Plants store glucose as starch  Animals store glucose as glycogen 38 40  FIBER LIPIDS  Includes various indigestible carbohydrates  Fat, oils, and cholesterol derived from plants  Saturated fats (solids at room temperature)  Food sources rich in fiber include beans, peas, usually come from animals nuts, fruits, and vegetables  Exceptions are palm oil and coconut oil  Technically, fiber is not a nutrient for humans  Contain mostly saturated fats  Cannot be digested  Butter and meats, such as marbled red meats and bacon,  Soluble fiber combines with bile acids and contain saturated fats cholesterol in the  small intestine and prevents them from being  Unsaturated fatty acids are found in plant oil absorbed 41 43 FIBER RICH FOOD FOOD HIGH IN TRANS-FAT 42 44  PROTEINS EXERCISE FOR GOOD HEALTH  Adequate protein formation requires 20 different types of amino acids  Adults require 8 from the diet, children require 9 essential amino acids  Some foods, such as meat, milk, and eggs, provide all 20 (complete)  Vegetables supply one or more essential amino acids, but are deficient in at least one (incomplete)  Vegetarians should combine plant products to provide all the essential amino acids 45 47 DIET AND OBESITY VITAMINS and MINERAL  Too many calories from any source  Vitamins contributes to body fat.  Organic compounds the body is unable to  Increases risk of obesity and associated produce, but are required for metabolic illnesses purposes  Must be obtained externally  Type 2 diabetes and cardiovascular  Antioxidants disease are often seen in people who are  Cellular metabolism generates free radicals obese. that carry extra electron  Vitamins C, E, and A are believed to defend the body against free radicals 46 48  VITAMINS and MINERAL  MINERALS  The body needs about 20 elements for various physiological functions 49 Page 648 Vitamin D  Skin cells contain precursor cholesterol molecule  Converted to vitamin D after UV exposure  Activated into calcitriol that regulates calcium uptake and metabolism 50