Feed Me! The Digestive System

Fact or Fiction Write agree or disagree next to each statement then give a reason for your response. Discuss your responses with your table. Athletes need more protein in their diets than other people do. The only salt that food contains is the salt that you have added to it. As part of a healthy diet, everyone should take vitamin supplements. You can go without water for longer than you can go without food.

Fact or Fiction All of the statements are FALSE!!! Athletes would only need additional protein if they were on an extreme training regimen. Plants obtain salts from the soil and animals then eat plants. A balanced diet should contain all the necessary vitamins. A healthy human could not survive more than a few days without water and in some conditions only hours.

Main function of the Digestive System Breaks down food into molecules the body can use The molecules are absorbed into the blood and carried throughout the body Wastes are eliminated from the body

Structures of the Digestive System Mouth Esophagus Stomach Small intestine Large intestine Liver

Kinds of Digestion Mechanical digestion – Physical change occurs as the food is broken down into smaller pieces. What are some other examples of physical changes? Putting food in a blender Using a knife to cut food Dissolving sugar in water Stirring or blowing on food to cool

Kinds of Digestion Chemical digestion – Chemical change happens as the nutrients in the food are broken apart. What are some other examples of chemical changes? Cooking food (not just heating up) Mixing vinegar and baking soda Burning paper (or food ) Cellular respiration releasing energy in food.

What happens? During chemical digestion Larger molecules are broken down into smaller molecules Carbohydrates are broken into sugar Bread, Pasta, Cereal, Sugars Proteins are broken into amino acids Beef, Chicken, Nuts, Legumes

1. Mouth Mechanical digestion occurs when you bite and chew Chemical digestion occurs when an enzyme in saliva breaks down the food.

2. Esophagus A muscular tube that connects your mouth to your stomach. Smooth muscles contract to push the food down in a process called peristalsis.

3. Stomach Expands to fit all the food you eat. Most of the mechanical digestion happens here because of the smooth muscle that churns the stomach. Chemical digestion takes place using enzymes.

4. Small Intestine Where most chemical digestion takes place. Absorption of nutrients begins here through many tiny villi (finger-like folds). Bile (produced in the liver) helps to break down the fat molecules.

5. Liver Produces bile that breaks down fat molecules. Bile is stored in the gallbladder and released into the small intestine.

6. Large Intestine Water is absorbed and returned to the blood stream. Materials not used are readied for elimination from the body.

Energy Transfer through Digestion The food we eat is storing energy in the form of chemical energy (glucose). As the food is broken down, the energy is transferred into heat or thermal energy.

Why do we need food? Food provides your body with materials for growing and for repairing tissues. Food also provides energy for everything we do. 6 nutrients needed for human health: Carbohydrates Fats Proteins Vitamins Minerals Water

Digestive System Diagram Color and label the following organs Esophagus (red) Stomach (yellow) Pancreas (purple) Rectum (blue) Small intestine (lt. red/pink) Large intestine (orange) Liver (brown) Gall Bladder (green)