Digestive System
Digestive System Rap
Job of Digestive System Break down food (macromolecules) into nutrients & energy
Review: Macromolecules What macromolecules do we eat? Proteins: Meat, Nuts Lipids: Oils, Fats Carbohydrates: Breads, Sugars
Review: Food Energy Which macromolecule is our main energy source? Carbohydrates
Which macromolecule stores the most energy? Lipids Review: Food Energy (cont.)
The Food Pyramid
Nutrition Nutrients: Anything that promotes growth Vitamins (Vitamin C) Minerals (Iron) Macromolecules
Two Types of Digestion Mechanical – physically breaking food into smaller pieces (mouth) Chemical – food molecules are broken down by acids and enzymes (stomach, small intestines)
Digestive System
Tracking a Piece of Food 1. Mouth 2. Esophagus 3. Stomach 4. Small Intestine 5. Large Intestine 6. Rectum 7. Anus
Swallowing Peristalsis: wavelike movement of muscles pushes food through digestive tract
My food went down the “wrong pipe!” 2 tubes in throat: trachea & esophagus esophagus connects mouth to stomach How does food know which tube to go down? epiglottis
3 Jobs of Stomach 1. Store food & liquid 2. Mix food & digestive juices (HCl) 3. Empty into small intestine
Digestive Juices Assist in breaking down of food Ex. Enzymes Acid Reflux
Small Intestine Absorbs greatest amount of nutrients Covered with tiny finger-like projections – villi ~20 ft long!
Villi Increase surface area for better absorption (like a towel)
Large Intestine Prepares waste for removal by absorbing water ~5 ft long!
Digestion: ‘Helper’ Organs Salivary Glands: produce saliva – starts breaking down carbohydrates Pancreas: produces enzymes & regulates glucose levels
Liver: Produces bile Filters blood Digestion: ‘Helper’ Organs (cont.)
Gall Bladder: stores bile Helps digest fatty foods Digestion: ‘Helper’ Organs (cont.)