OverviewConcept 41.1: An animal’s diet must supply chemical energy, organic molecules, and essential nutrientsEssential Amino AcidsPowerPoint PresentationEssential Fatty AcidsSlide 6MineralsAssessing Nutritional needs and Dietary DeficienciesUndernourishmentConcept 41.2: The main stages of food processing are ingestion, digestion, absorption, and eliminationSlide 11Slide 12Digestive CompartmentsSlide 14Slide 15Slide 16Concept 41.3: Organs specialized for sequential stages of food processing form the mammalian digestive systemSlide 18The Oral Cavity, Pharynx, and EsophagusSlide 20Digestion in the StomachSlide 22Digestion in the Small IntestineSlide 241. Pancreatic Secretions3. Secretions and absorptions in the Small IntestineSlide 27Absorption in the Large IntestineConcept 41.4: Evolutionary adaptations of vertebrate digestive systems correlate with dietSlide 30Stomach and Intestinal AdaptationsSlide 32Concept 41.5: Homeostatic mechanisms contribute to an animal’s energy balanceOvernourishment and ObesitySlide 35Slide 36Slide 37Slide 38Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsOverview•Food is taken in, taken apart, and taken up in the process of animal nutrition •In general, animals fall into three categories:–Herbivores eat mainly autotrophs (plants and algae)–Carnivores eat other animals–Omnivores regularly consume animals as well as plants or algal matterCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsConcept 41.1: An animal’s diet must supply chemical energy, organic molecules, and essential nutrients•An animal’s diet provides chemical energy, which is converted into ATP and powers processes in the body•Animals need a source of organic carbon and organic nitrogen in order to construct organic molecules•Essential nutrients are required by cells and must be obtained from dietary sources. There are 4classes of essential nutrients:1. Essential amino acids2. Essential fatty acids3. Vitamins4. MineralsCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsEssential Amino Acids•Animals require 20 amino acids and can synthesize about half from molecules in their diet•The remaining amino acids, the essential amino acids, must be obtained from food in preassembled form•A diet that provides insufficient essential amino acids causes malnutrition called protein deficiency•Meat, eggs, and cheese provide all the essential amino acids and are thus “complete” proteins•Individuals who eat only plant proteins need to eat specific plant combinations to get all essential amino acidsFig. 41-2Beans and otherlegumesCorn (maize)and other grainsLysineEssential amino acids for adultsTryptophanIsoleucineLeucinePhenylalanineThreonineValineMethionineCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsEssential Fatty Acids•Animals can synthesize most of the fatty acids they need•The essential fatty acids are certain unsaturated fatty acids that must be obtained from the diet. Deficiencies in fatty acids are rare•Vitamins are organic molecules required in the diet in small amounts•13 vitamins essential to humans have been identified•Vitamins are grouped in 2 categories: fat soluble & water solubleVitaminsTable 41-1MineralsMinerals are simple inorganic nutrients, usually required in small amountsCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsAssessing Nutritional needs and Dietary Deficiencies•Insights into human nutrition have come from epidemiology, the study of human health and disease in populations•Undernourishment is the result of a diet that consistently supplies less chemical energy than the body requires•Malnourishment is the long-term absence from the diet of one or more essential nutrientsCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsUndernourishment•An undernourished individual will –Use up stored fat and carbohydrates–Break down its own proteins and lose muscle mass–Suffer protein deficiency of the brain–Die or suffer irreversible damage •Malnourishment can cause deformities, disease, and death•Malnourishment can be corrected by changes to a dietMalnourishmentCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsConcept 41.2: The main stages of food processing are ingestion, digestion, absorption, and elimination1. Ingestion is the act of eating, 4 kindsa. Suspension Feeders- Many aquatic animals are suspension feeders, which sift small food particles from the water. E.g Whaleb. Substrate Feeders- These are animals that live in or on their food source. E.g.: Caterpillarc. Fluid Feeders- are those that suck nutrient-rich fluid from a living host. E.g. Mosquitod. Bulk feeders eat relatively large pieces of food e.g. human, PythonCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings2. Digestion is the process of breaking food down into molecules small enough to absorb–In chemical digestion, the process of enzymatic hydrolysis splits bonds in molecules with the addition of water3. Absorption is uptake of nutrients by body cells4. Elimination is the passage of undigested material out of the digestive compartmentFig. 41-7Ingestion DigestionAbsorptionEliminationUndigestedmaterialChemical digestion(enzymatic hydrolysis)Nutrientmoleculesenter bodycellsSmallmoleculesMechanicaldigestionFoodPiecesof food1234Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin CummingsDigestive Compartments•Most animals process food in specialized compartments•These compartments reduce the risk of an animal digesting its own cells and tissuesa) In Intracellular digestion, food particles are engulfed by endocytosis and digested within food vacuolesb) Extracellular digestion is the breakdown of food particles outside of cells•It occurs in compartments that are continuous with the outside of the animal’s bodyCopyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings1. Animals with simple body plans have a gastrovascular cavity that functions in both digestion and distribution of nutrients2. More complex animals have a digestive tube with two openings, a mouth and an anus•This digestive tube is called a complete digestive tract or an alimentary canal•It can have specialized regions that carry out digestion and absorption in a stepwise fashionTwo kinds