The Human Digestive System

What is the digestive system? Your cells need a lot of energy for daily activities. Cells use nutrients, which are substances in food, for energy, growth, maintenance, and repair. The digestive system breaks down the food you eat into nutrients that can be used as building materials and that can provide energy for cells.

What are the two types of digestion? Digestion is the process of breaking down food into a form that can pass from the digestive system into the bloodstream. There are two types of digestion: mechanical and chemical.

What are the two types of digestion? Mechanical Digestion Is the breaking, crushing, and mashing of food. Ex: Chewing is a type of mechanical digestion. Chewing creates small pieces of food that are easier to swallow and digest than large pieces are.

What are the two types of digestion? Chemical Digestion Is the process in which large molecules of food are broken down into smaller molecules so that they can pass into the bloodstream. An enzyme is a chemical that the body uses to break down large molecules into smaller molecules. Enzymes act like chemical scissors, they “cut up” large molecules into smaller pieces. *Without mechanical digestion, chemical digestion would take days instead of hours*

Decide if these are mechanical/chemical In your mouth, teeth grind food mechanical chemical In the small intestine, most nutrients are broken down by enzymes

Decide if these are mechanical/chemical In your mouth, teeth grind food mechanical chemical In the small intestine, most nutrients are broken down by enzymes

What are the parts of the digestive system? The Mouth The Esophagus Stomach Small Intestine Large Intestine

What are the parts of the digestive system? http://goo.gl/pz0Iu2

What are the parts of the digestive system? The Mouth Digestion begins in the mouth with both mechanical and chemical digestion. Teeth, with the help of the jaw, break and crush food. As you chew, food is moistened by saliva. Saliva contains many substances, including an enzyme that begins the chemical digestion of starches in food.

What are the parts of the digestive system? The Esophagus Once food has been chewed, it is swallowed and moves through the throat and a long tube called the esophagus. Waves of muscle contractions move food into the stomach. Ex: muscle moves food along the same way you move toothpaste from the bottom of the tube with your thumbs

What are the parts of the digestive system? Stomach The stomach is a muscular bag that crushes food and contains acids and enzymes for killing bacteria and breaking down protein. The stomach wall contains layers of muscle so the stomach can churn and mix food. This is the final step of mechanical digestion. Food sits in the stomach for a few hours before moving to….. http://goo.gl/DHab2d

What are the parts of the digestive system? Small Intestine The small intestine is a muscular tube were most chemical digestion takes place. Most nutrients are absorbed in the small intestine as well. Food travels from the stomach into the small intestine in the form of chyme. Chyme is food reduced to a soupy mixture

What are the parts of the digestive system? Large Intestine After food moves through the small intestine, it moves to the large intestine. In the large intestine, water and nutrients are absorbed. Most solid material that remains is waste Waste is compacted and stored until the body eventually eliminates it. http://goo.gl/pz0Iu2

Where are nutrients absorbed? After nutrients are broken down, they are absorbed into the blood stream and used by cells Removes water from mostly-digested foods, absorbs vitamins, and turns food waste into semi-solid waste. Small Intestine Large Intestine

Other organs that help digest nutrients Pancreas-makes fluids that break down every type of material found in foods Ex: these include proteins, carbohydrates, fats, and nucleic acids Liver-makes and releases a mixture called bile that is stored in the gall bladder Bile breaks up large fat droplets into very small fat droplets

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Facts about the Digestive System HOW LONG ARE YOUR INTESTINES? At least 25 feet in an adult. Be glad you're not a full- grown horse -- their coiled-up intestines are 89 feet long! Chewing food takes from 5-30 seconds Swallowing takes about 10 seconds Food sloshing in the stomach can last 3-4 hours

Facts about the Digestive System It takes 3 hours for food to move through the intestine Food drying up and hanging out in the large intestine can last 18 hours to 2 days! Americans eat about 700 million pounds of peanut butter. Americans eat over 2 billion pounds of chocolate a year. In your lifetime, your digestive system may handle about 50 tons!!

Brainpop http://www.brainpop.com/health/bodysyste ms/digestivesystem/

Discussion Questions What does the digestive system do? The digestive system breaks down food into small particles that the body can absorb and use. What are enzymes? Enzymes are proteins that help break down larger molecules into smaller molecules. What happens to an enzyme after it helps break down a food molecule? The enzyme does not change, so it can be used to break down another food particle.

Discussion Questions Which organ connects the mouth to the stomach? the esophagus Why is the stomach's ability to store food beneficial? Because the stomach stores food, you can go hours between meals. Where does food go after it leaves the stomach? It enters the small intestine.

Discussion Questions What organs work together to help with chemical digestion? mouth, esophagus, stomach, small intestine, pancreas, liver, and gallbladder What might happen to other body systems if the digestive system did not function properly? Answers will vary. The other body systems would not be able to get the nutrients they need to function.