Chapter 41 Digestion 10 15 2015 Animals are all heterotrophic and require an array of raw materials and sources of energy Use them for synthesis of compounds that we need in our body Digestion enzymatic hydrolysis breaking proteins down into amino acids by adding water Need enzymes to carry out these reactions 1 nonphotosynthetic bacteria 2 nonphotosynthetic protists defined by what they eat amoeba bring food in through pseudopodia fuse with lysosome paramecium food brought in through oral groove and cytostome makes food vacuole that fused with lysosome and anal pore releases waste live on food parasitic or saprobic 3 fungi absorptive 4 animals ingestive defined by what they eat carnivores meat eaters herbivores eat plant material only omnivores eat both plants and animals suspension feeders and filter feeders Baleen hair like teeth that capture crustaceans Substrate feeders Insects that mine through the middle of the leaves Fluid feeders Spiders and mosquitoes Female mosquitoes need your blood to develop their eggs Bulk feeders Snakes have the ability to unhinge their jaws FIGURE 41 7 Gastrovascular cavities allow for larger portions to be consumed Alimentary canals Runs from mouth through anus Food comes in one way and out the other Crop like a stomach where food can be stored Gizzard structures that help grind food up animals with out teeth birds may add pebbles to their gizzards Ability to eat while still digesting Typhlosoles increase surface area folds in earthworms digestive systems to fit more food 1 Ingestion mechanical digestion 2 Digestion Chemical digestion adding water by use to enzymes to breakdown food 3 Absorption all of the good stuff goes back into the body 4 Elimination anything that can t be digested is eliminated what food is has to be learned taught what it is cultural taste is somewhat genetic can taste certain chemicals compared to other people 1 look at the food 2 Smell the food 3 Taste the food 4 Texture 5 Temperature 6 Swallow FIGURE 41 9 memorize and know what happens in each organ Mouth Pallet top of the mouth hard bony front v soft muscular back o Ends in uvula o Separates mouth from nasal passage Teeth o Incisor bite with o Canine for tearing o Pre molars for grinding o Molars for crushing o Structure of the tooth Enamel outside hard calcium covering hardest substance in human body Crown part above gum Root below gum Dentine thick bone like under enamel Pulp majority of vessels and nerves are o Carnivore a lot of canines o Herbivore incisors for grinding plants o Omnivores a mix of both fore eating meat and plants Salivary glands o o o o o o o o o o o o FIGURE Reflex causes release of saliva Smells can cause this Helps move food down throat Some digestion occurs here 3 major pairs of salivary glands parotid in cheeks below and in front of teeth produce watery saliva open over second molar sublingual under tongue produce both watery and mucous saliva submandibular beneath the lower jaw produce both types of saliva watery salvia moisten foods mucous saliva helps stick food together bolus little ball of food moving down throat saliva cleans mouth keeps it from drying out helps you be able to speak buffers in the saliva for acidic foods thiocyanate ion produce 1 5 liters of saliva a day 41 12 MEMORIZE AND KNOW EVERYTHING ABOUT IT o Salivary amylase works on polysaccharides like starch and glycogen breaks down into maltose doesn t work very long o pH of mouth 6 5 6 8 o Stomach is very acidic and it denatures salivary amylase Pharynx Larynx o Voice box o Goes up when swallowing o Epiglottis closes trachea when swallowing food Peristalsis how we move food throughout the body Mixture of relaxed muscles and contracted muscles Squeeze push squeeze push Sphincter ring of muscle Opening of stomach has a ring of smooth muscle When pressure put on muscle it opens Lumen opening Mucosa an epithelial layer that lines the lumen Submucosa a matrix od connective tissue that contains blood vessels and nerves Muscularis consists mainly of smooth muscle tissue Serosa a think layer of connective and epithelial tissue Stomach Holds about 2 liters Muscle layers running all ways throughout for churning kneading Mixes food with digestive enzymes Rugae Folds of epithelial tissue Upper region of the stomach is known as the cardiac region cardiac sphincter Fundus middle region of the stomach Pyloric region lower part with the pyloric sphincter Gastric pits line interior surface of the stomach that leads to three types of cells o Mucous cells produce mucous o Chief cells pepsinogen o Parietal cells hydrochloric acid Zymogen inactive version of an enzyme When pepsinogen is mixed with hydrochloric acid it creates pepsin by exposing the active site of the enzyme Pepsin can work back on pepsinogen and make it active Pepsin begins to break down proteins making them into smaller polypeptides by hydrolytic acid The release of pepsinogen is affected by a hormone Hormone chemical signal released by own part of the body and travels to another to tell it to do something Gastrin produced by the lower part of the stomach and travels through the blood to the upper part of the stomach it affects the release of hydrochloric acid and pepsinogen If the stomach is too acid gastrin is turned off and hydrochloric acid is stopped by negative feedback pH of the stomach is about 3 the acid breaks apart the glue that holds cells together bacteria causes ulcers helicobacter pylori mucous layer of the stomach and pepsinogen protects the stomach from the acid protect it from being digested cells in the stomach last about three days and then they are replaced a lot of mitosis occurs in the stomach and intestines cancer drugs attack cells that are rapidly dividing so sometimes will attack stomach and intestinal cells chyme semi liquid state of digested food pyloric sphincter opens because presence of chyme and slow down of churning Small intestine About 20 ft long Name comes from diameter Carnivore has longer more small intestine Herbivore has a longer large intestine and overall have longer intestinal systems because plants are harder to digest Rest of digestion completed Absorption 3 parts of the small intestine o duodenum o jejunum o ileum liver is constantly secreting green bile that contains the breakdown products of hemoglobin bile is stored and released by the gull bladder hormone secreted from duodenum CCK chlerysto kinin that tells the gull bladder to release bile digestion is enzymatic hydrolysis