BIOL 205 Lecture Notes - Lecture 9: Gastrointestinal Tract, Human Digestive System, Salivary Gland
21 Oct 2016
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Biol 205 - chapter 26 - nutrition in animals. Most chordates (including humans) ingest food through their mouth, nutrients are digested into smaller molecules for absorption in the intestines, and wastes are expelled. Three dietary categories: herbivores: eat mainly autotrophs (producers or plants/algae) (ie. cattle, gorillas, snails, carnivores: eat mainly other animals (ie. lions, spiders, whales, omnivores: consumes both plants and animals (ie. humans, crows, raccoons) Digestion: breaking down food into small molecules (breaks. Chemical digestion: allows the body to break down large biological macromolecules in a specialized compartment (ie. food vacuole in single cells; gastrovascular cavity in simple organisms) without digesting itself. Crop: similar to a stomach but stores and softens food. Stomach or gizzard: may store food temporarily (churn or grind food) Length of digestive tract relates to diet (herbivore has longer alimentary canal because plants take longer to digest, also includes a special segment that secretes enzymes/bacteria to break down cellulose)
