3 The Digestive System Purpose: How is food digested? Break down food into small pieces that cells can use.How is food digested?Mechanical break down of food into smaller pieces = physical changeMixing of foodMovement through the digestive tractChemical break down of big molecules of food into smaller molecules = chemical change
4 Mouth Physical (Mechanical) digestion – teeth Chewing – breaks food into small piecesChemical digestion – salivaEnzymes in the saliva begin digestion of carbohydrates.
5 Esophagus Muscular tube Physically moves food to stomach using waves of muscle contractions called peristalsis.
6 Stomach Produces strong digestive juices. Chemical Digestion breaks down and dissolves food nutrients.Digests proteins and fats in the stomach
7 Small Intestine Enzymes continue the chemical digestion of food. Nutrients are broken down small enough to go through the VILLI of small intestine, and into bloodDigests proteins, fats, and carbohydrates. Digestion Completed Here
8 Pancreas Accessory organ Food does not enter the pancreas Produces chemicals to help break down macromolecules (big molecules) = chemical difestion
9 LiverProduces bile to help digest fat = mechanical digestion = physical changeBile is Stored in the Gallbladder
10 Large Intestine (Colon) Absorbs dissolved nutrients & waterNO DIGESTIONForms wastes into solid fecesPhysical Change