Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Animal Nutrition Human Digestion
Transcript
Animal Nutrition Human Digestion Regents Biology 2006-2007 What do animals need to live? § Animals make energy using: food u oxygen u food § Animals build bodies using: u food for raw materials § amino acids, sugars, fats, nucleotides u ATP O2 ATP energy for synthesis Regents Biology mitochondria How do animals get their food? filter feeding Regents Biology fluid feeding living in your food bulk feeding Regents Biology Different diets; different lives § All animals eat other organisms u Herbivores § eat mainly plants w gorillas, cows, rabbits, snails u Carnivores § eat other animals w sharks, hawks, spiders, snakes u Omnivores § eat animals & plants w cockroaches, bears, raccoons, humans w humans evolved as hunters, scavengers & gatherers Regents Biology Getting & Using Food § Ingest u taking in food § Digest u mechanical digestion § breaking up food into smaller pieces u chemical digestion § breaking down food into molecules small intracellular digestion enough to be absorbed into cells § enzymes § Absorb u absorb nutrients across cell membranes § diffusion § active transport § Eliminate u undigested material passes out of body Regents Biology extracellular digestion Digestive systems Everybody’s got one! Regents Biology Human digestive system Regents Biology Mouth § Functions u mechanical digestion § teeth w break up food u chemical digestion (saliva) § amylase enzyme w digests starch § mucus w protects soft lining of digestive system w lubricates food for easier swallowing § buffers w neutralizes acid to prevent tooth decay § anti-bacterial chemicals Regents Biology w kill bacteria that enter mouth with food All that in spit! Swallowing (& not choking) § Epiglottis flap of cartilage u closes trachea (windpipe) when swallowing u food travels down esophagus u § Peristalsis u involuntary Regents Biology muscle contractions to move food along mouth §break up food §digest starch §kill germs §moisten food Regents Biology Stomach § Functions disinfect food u § hydrochloric acid = pH 2 w kills bacteria food storage u § can stretch to fit ~2L food begins digests protein u § pepsin enzyme from pancrease But the stomach is made out of protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects Regents Biology stomach lining mouth §break up food §digest starch §kill germs §moisten food stomach §kills germs §break up food §digest proteins §store food sphincter sphincter Regents Biology Ulcers Colonized by H. pylori § Ulcers caused Free of H. pylori by excessive HCl § New medicines actually control the cells that secrete the HCl into the stomach. inflammation of stomach inflammation of esophagus H. pylori inflammatory proteins (CagA) cell damaging proteins (VacA) ✗ ✗ cytokines helper T cells neutrophil cells white blood cells Regents Biology Small intestine § Functions u digestion § digest carbohydrates w amylase from pancreas § digest proteins w Pepsin from pancreas § digest lipids (fats) w bile from liver u absorption § nutrients move into body cells by: w Diffusion into blood stream Regents Biology This is where all the work is done! Absorption in Small Intestines § Absorption through villi & microvilli finger-like projections u increases surface area for absorption u SMALL INTESTINES 6 meters long, but can stretch to cover a tennis court Regents Biology mouth §break up food §digest starch §kill germs §moisten food liver §produces bile - stored in gall bladder §break up fats pancreas §produces enzymes to digest proteins Regents Biology stomach §kills germs §break up food §digest proteins §store food small intestines §breakdown food - proteins - starch - fats §absorb nutrients Pancreas § Produces digestive enzymes u digest proteins § Pepsin u digest starch § Amylase § Buffers u neutralizes acid from stomach Regents Biology small intestine pancreas mouth §break up food §digest starch §kill germs §moisten food pancreas §produces enzymes to digest all foods Regents Biology stomach §kills germs §break up food §digest proteins §store food Liver & Gall Bladder § Produces bile breaks up fats u gallbladder only stores bile u § that’s why you can have your gall bladder removed bile contains colors from old red blood cells collected in liver = iron in RBC rusts & Regentsfeces Biology makes brown mouth §break up food §digest starch §kill germs §moisten food liver §produces bile - stored in gall bladder §break up fats pancreas §produces enzymes to digest proteins & starch Regents Biology stomach §kills germs §break up food §digest proteins §store food Large intestines (colon) § Function u re-absorbs water § use ~9 liters of water every day in digestive juices w if don’t reabsorb water would die of dehydration § > 90% of water re-absorbed w not enough water re-absorbed n diarrhea n can be fatal! w too much water re-absorbed n constipation Regents§ Biology reabsorb by diffusion You’ve got company! § Living in the large intestine is a community of helpful bacteria u PEE-YOO! Escherichia coli: E. coli § digest cellulose w digests fruits & vegetables § produce vitamins w vitamin K & B vitamins § BUT generate gases w by-product of bacterial metabolism w methane, hydrogen sulfide w STINKY! Regents Biology mouth §break up food §digest starch §kill germs §moisten food liver §produces bile - stored in gall bladder §break up fats pancreas §produces enzymes to digest proteins & carbs Regents Biology stomach §kills germs §break up food §digest proteins §store food small intestines §breakdown food - proteins - starch - fats §absorb nutrients large intestines absorb water Appendix Vestigial organ Regents Biology mouth §break up food §digest starch §kill germs §moisten food liver §produces bile - stored in gall bladder §break up fats pancreas §produces enzymes to digest proteins & carbs appendix Regents Biology stomach §kills germs §break up food §digest proteins §store food small intestines §breakdown food - proteins - starch - fats §absorb nutrients large intestines absorb water Rectum § Last section of large intestines learn to control this muscle u what’s left over? u § undigested materials w mainly cellulose from plants w called roughage or fiber w keeps everything moving & cleans out intestines § masses of bacteria Regents Biology So don’t forget to wash your hands!
