Living creatures are ORGANIZED

1. Living creatures are ORGANIZED • All made of the same collection of chemicals, but we are organized as… • molecules • proteins, fats, carbohydrates, nucleic acids carbohydrates proteins DNA

2. Living creatures are ORGANIZED • All made of the same collection of chemicals, but we are organized as… • organelles & cells • plant cells & animal cells plant cell animal cell

3. Getting from there to here… • Going from a cell to baby…. the original fertilized egg has to divide… The groups of cells work together to perform the same function as tissue. Groups of tissue work together as a system

4. Living creatures are ORGANIZED • All made of the same collection of chemicals, but we are organized as… • organs & organ systems • respiratory, circulatory, digestive, etc.

5. food O2 ATP What do animals need to make the systems work • Animals make energy using: • food • oxygen • Animals build bodiesusing: • food for raw materials • amino acids, sugars, fats, nucleotides • ATP energy for synthesis mitochondria But where do we get the raw material from?

6. We EAT IT!

7. Different diets; different lives • All animals eat other organisms • Herbivores • eat mainly plants • gorillas, cows, rabbits, snails • Carnivores • eat other animals • sharks, hawks, spiders, snakes • Omnivores • eat animals & plants • cockroaches, bears, raccoons, humans • humans evolved as hunters, scavengers & gatherers

8. Getting & Using Food • Ingest • taking in food • Digest • mechanical digestion • breaking up food into smaller pieces (bolus) • chemical digestion • breaking down food into molecules small enough to be absorbed into cells • enzymes • Absorb • absorb across cell membrane • diffusion • active transport • Eliminate • undigested material passes out of digestive system intracellulardigestion extracellulardigestion

9. Digestive systems Everybody’s got one!

10. Human digestive system

11. Ingestion- where it all starts! • Mouth • mechanical digestion • teeth • breaking up food • chemical digestion • saliva • enzyme digests starch • Carbohydrate (chains of sugars) • slippery protein • protects soft lining of digestive system • lubricates food for easier swallowing

12. mouth break up food digest starch kill germs moisten food

13. Stomach • Functions • food storage • can stretch to fit ~2L food • disinfect food • HCl = pH 2 • kills bacteria • chemical digestion • enzyme breaks down proteins • In to amino acids But the stomach is made out of protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects stomach lining

14. stomach kills germs break up food digest proteins store food mouth break up food digest starch kill germs moisten food sphincter sphincter

15. Small intestine • Function • chemical digestion • major organ of digestion & absorption • absorption through lining • over 6 meters! • small intestine has huge surface area = 300m2 (~size of tenniscourt) • Structure • 3 sections • duodenum • jejunum • Ileum\

16. Duodenum • 1st section of small intestines • acid food from stomach • mixes with digestive juices from: • pancreas • liver • gall bladder

17. Pancreas • Digestive enzymes • digest proteins – into amino acids • digest starch- in to sugars • Buffers • neutralizes acid from stomach

18. pancreas produces enzymes to digest proteins & starch mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food

19. Liver • Function • produces bile • bile stored in gallbladder until needed • breaks up fats – nonpolar! bile contains colors from old red blood cells collected in liver = iron in RBC rusts & makes feces brown

20. liver produces bile - stored in gall bladder break up fats mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food pancreas produces enzymes to digest proteins & starch

21. Absorption by Small Intestines • Absorption through villi & microvilli • finger-like projections • increase surface area for absorption

22. small intestines breakdown food - proteins - starch - fats absorb nutrients mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats pancreas produces enzymes to digest proteins & starch

23. Large intestines (colon) • Function • re-absorb water • use ~9 liters of water every day in digestive juices • > 90% of water reabsorbed • not enough water absorbed • diarrhea • too much water absorbed • constipation

24. You’ve got company! • Living in the large intestine is a community of helpful bacteria • Escherichiacoli (E. coli) • produce vitamins • vitamin K; B vitamins • generate gases • by-product of bacterial metabolism • methane, hydrogen sulfide

25. large intestines absorb water mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food liver produces bile - stored in gall bladder break up fats small intestines breakdown food - proteins - starch - fats absorb nutrients pancreas produces enzymes to digest proteins & carbs

26. Appendix Vestigial organ

27. Rectum • Last section of colon (large intestines) • eliminate feces • undigested materials • extracellular waste • mainly cellulose from plants • roughage or fiber • masses of bacteria