LC-DigestiveSystemNotes

Digestive System Notes 10-9-07

Why do we eat? Energy, and Matter....the building blocks of life...atoms How do we lose matter? Break it down, waste, cell death, Calories- measure of energy in food We consume too much energy Fat- certain type of nutrient - We need fat (lipid) to make up the cell membrane, insulate, use long term energy. - Bad fats: Saturated (come from animals; solid at room temperature), and Trans(man-made fat) - Cholesterol: associated with heart disease - Sodium: associated with high blood pressure - 5% little -20% high in diet - Carbohydrates: Good carb (fiber) - Plant material Bad Carb (sugar) - pure sugar Protein - Amino acids - DNA comes from protein - Essential amino acids are vital - Good protein sources: animals. Protein in the muscles. Chicken, cow, fish, wheat, milk, eggs, nuts Vitamin A - not an energy source - important molecule - Eyesight - Carrots Vitamin C - Immune System - Orange juice - Scurvy - Makes a protein called collagen- 25% of the protein in your body is collagen. - connective tissue - filler protein Calcium - Bones Iron - red blood cells that carry oxygen

How do these molecules get into your body? - Digestive system breaks down food to get to cells. - Mouth, 20 feet tube, digest the food and absorb the energy you need. - Mouth- chew mechanical digestion- one chemical absorbed in mouth-sugar - microscopic food pieces - Down the tube and into the stomach - Acid and stomach muscles breaks down the food almost microscopic - chemically digested in stomach-protein - hits small intestine and chemical digestion occurs - small enough pieces into which it can cross a cell. - small intestine has tons of fold. Surface of a tennis court. Large intestine eats up the food you don't want. - Friendly bacteria eat the things we can't digest. - Water is absorbed - gets more firm - 2 hours in your stomach. - small intestine for the next 4 hours - sits in large intestine- water is absorbed - spends 27 hours in large intestine and then is excreted. -mouth, tube through intestines is about 33 hours...