BIOL 1361 1nd Edition Lecture 3 Outline of Last Lecture I. An end to Ulcers? – Case Study in the Scientific MethodII. Important Aspects of Experimental DesignOutline of Current Lecture I. Essential Nutrients for AnimalsII. Ingestion & DigestionIII. Intracellular and Extracellular DigestionIV. Gastrovascular CavityV. Alimentary Canal = “Gut”VI. Digestive SystemCurrent LectureI. Essential Nutrients for Animalsa. Amino Acidsi. Humans need 20, can make ~10 if have enough N & Sb. Unsaturated fatty acidsi. Acquired from plantsc. Vitamins – Carbon containingd. Mineralsi. Inorganic molecules: Fe, Mg, I, Cae. Bunny:i. 1. Ingestionii. 2. Digestioniii. 3. Absorptioniv. 4. EliminationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.II. Ingestion and Digestiona. Ingestion = Feedingb. Digestioni. Breaking down food into small molecules1. Enzymes catalyze hydrolysis of chemical bondsii. Digestive compartments protect animal from self-digestionIII. Intracellular and Extracellular Designa. Intracellular Digestioni. Amoeba attempts to ingest a yeast cellii. Food taken in by phagocytosisiii. Digested in vacuole1. Ex. Amoebab. Extracellular Digestioni. Digest food in compartments continuous with outside of bodyii. Nutrients absorbed from exterior compartment across cell membranes and into body fluidsIV. Gastrovascular Cavitya. Is a digestive compartment with 1 openingi. Food in, waste out same wayii. Digestive secretions enter cavityiii. Prey is digestediv. Nutrients are absorbed by body cellsV. Alimentary Canal = “Gut”a. 1-way tubeb. Most animals have thisc. Specialized Compartments for Digestions (Fig 33.8)i. Focus on vertebrate digestive tractd. Cat Digestive System – superficialVI. Digestive Systema. Mouth, pharynx, esophagusi. Chew, swallow, move to stomachii. Secretions1. Amylase – digests starch2. Mucus – lubrication3. Movement = peristalsisa. Alternate contraction of circular and longitudinal muscles to move food downwardb. Stomachi. Mix and digest1. Secretionsa. HCli. Denatures proteinb. Pepsini. Enzyme that breaks down proteinsc. Mucusi. Protects and lubricatesii. Epithelium1. Sheet of cells lining body cavities and organs2. Produces secretions3. Provides barrier against injury, pathogens4. Mediates exchange with external environment5. Structure: Tight Junctionsa. Is the plasma membranes of neighboring cells bound together by proteinsb. Forms a continuous seal around cellc. Separate outside fluids from inside bodyd. Lumen – hollow space6. Function a. Proenzyme – inactive and part of it must be removed to activate the enzyme (things that end with gen)b. 1. Pepsinogen – a Proenzyme, is secreted into stomach lumenc. 2. HCl in lumen drolyzes pepsinogen to pepsind. 3. Pepsin can also hydrolyze pepsinogen to produce more pepsin c. Duodenumi. The upper part of small intestineii. Function: Digestion of peptides, lipids, sugarsiii. Secretions1. Enzymes from lining of intestine2. Pancreatic Secretion:a. HCO3 – neutralizes stomach acidsb. Enzymes3. Liver Secretions:a. Bile – emulsifies fatsd. Absorptioni. Small molecules move from outside cells to inside the bodyii. A. Small Intestine1. Jejunum & Ileum absorb nutrients & water2. Epithelial function = exchange3. Villi 4.
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