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Digestive system chapter 38-1 pg. 971-977

Digestive system chapter 38-1 pg. 971-977. Organization: how does our body get nutrients?. What nutrients do our bodies need?. Carbohydrates – energy Lipids – energy, cell membranes, insulation/ protection Proteins – Many different functions!. What else do our bodies need?.

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Digestive system chapter 38-1 pg. 971-977

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  1. Digestive systemchapter 38-1 pg. 971-977 Organization: how does our body get nutrients?

  2. What nutrients do our bodies need? • Carbohydrates – energy • Lipids – energy, cell membranes, insulation/ protection • Proteins – Many different functions!

  3. What else do our bodies need? • Water – our cells are filled with cytoplasm, which is made of mostly water • Vitamins – Molecules our bodies cant make, but need • Minerals – ions such as iron (Fe2+), Calcium (Ca2+), Sodium (Na+), and Potassium (K+)

  4. How do we get nutrients? • The function of the digestive system: • Break up complex molecules (food) into smaller pieces that our bodies can use

  5. 4 steps to get nutrients • Ingestions – take in food • Digestions – break down food • Absorption – move monomers to blood stream • Elimination – get rid of waste

  6. Primary & Accessory Organs • Primary: organs the food passes through • Accessory: food does not pass through, but help in digestion

  7. The Organs

  8. Mouth • Mechanical digestions: physically breaks apart food • Teeth  chew! • Chemical digestion: breaks chemical bonds • Saliva: • contains amylase  an enzyme that breaks down polysaccharides • Moistens food

  9. Esophogus • Peristalsis: the contraction of muscles in waves to move and crush the bolus, chewed food. • http://www.youtube.com/watch?v=rJS-Kh5wCQU • Epiglottis: flap that prevents food from going down your trachea (windpipe) when you swallow.

  10. Stomach • Chemical: HCl kills bacteria and activates pepsin enzymes • Pepsin breaks down polypeptides (protein) • Mechanical: muscles crush and mix food into chyme

  11. Small Intestine • Chemical: • Where most digestion takes place • pancreas and liver secrete enzymes into small intestine • Vili: many folds in the walls, which increase surface area for absorption

  12. Pancreas • Accessory organ • Has different types of cells to produce hormones and enzymes • Secretes (produces) enzymes into small intestine: • Amylase – breaks down starch • Trypsin – breaks down polypeptides • Lipase – breaks down triglycerides

  13. Liver • Accessory organ • Connect to the small intestine through the common bile duct • Secretes bile: • Bile emulsifiesfats = bile breaks up clumps of fat

  14. Gall Bladder • Accessory organ • Stores bile

  15. Large Intestine • No digestion • Removes water • Stores waste

  16. More Digestive Enzymes What chemical reaction do these enzymes catalyze ?

  17. Practice Essay • Can you describe what would happen to a slice of pepperoni pizza as it moves through your digestive system? • What macromolecules are in which parts of the pizza? • Where would those macromolecules be digested?

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