What goes in should have a purpose, what comes out is waste  Digestive System What goes in should have a purpose, what comes out is waste 

Why does the body need food? Food provides your body with materials for growth and repair of everything from cells up. Nutrients: substances in food that your body needs The raw material the body needs to do all the essential processes like growth, responding to surroundings, moving….. Energy: body needs energy from food to do work Calorie- amount of energy needed to raise the temperature of 1 g of water 1oC We need a certain amount of calories each day for the body to function, extra calories are needed for extra work Carbohydrates Fats (lipids) Proteins Vitamins Minerals Water

6 Essential Nutrients 1. Carbohydrates- provide energy and raw material for cells 2. Fats (Lipids) 3. Proteins 4. Vitamins 5. Minerals 6. Water

1. Carbohydrates- energy for the body and raw materials for cell parts Simple Carbohydrates Complex Carbohydrates Sugar Quick energy Easy to break down Starches Fiber Energy for later, take longer to digest (break down)

2.Fats (lipids)-energy and then some.. Fats provide more energy than an equal amount of carbohydrate Fats are needed to build cell membranes Fatty tissue protects and supports internal organs Fat provides insulation to body Kinds of Fats Cholesterol -body needs it, but liver makes it, so no need to eat it Unsaturated fats -liquid at rm temp (plant sources) Saturated fats -solid at room temp (animal sources)

3.Proteins-need for tissue growth and repair Proteins are an energy source, but Proteins are necessary to rebuild tissue Proteins are made of AMINO ACIDS Complete Proteins vs Incomplete Proteins

4. Vitamins

5. Minerals

Water

Organs of the Digestive System Where does food go? Where does digestion happen? How does food feed the body’s cells? Mechanical Digestion vs Chemical Digestion http://help4kids.stanford.edu/nutritiongr8/framework.swf

Digestion….MOUTH Both chemical and mechanical digestion begin in the mouth Teeth Saliva Enzymes (proteins that speed up chemical reactions) in saliva begin the digestion of starches into sugar

EPIGLOTTIS and ESOPHOGUS http://www.bing.com/images/search?q=epiglottis+and+esophagus&qs=SC&sk=&FORM=QBIR&pq=epiglotis%20and%20eso&sc=4-17&sp=2&qs=SC&sk=#view=detail&id=205B2F3DC7821E125FCEC816615EA0206D3EEF0D&selectedIndex=13 Food is pushed into the esophogus by the tongue The epiglottis assures that the food doesn’t enter the wind pipe (The wrong tube) Smooth muscles in the esophogus push the (chyme) mushed up food down into the stomach. http://strokengine.ca/family/images/swallow.gif

STOMACH This is where MOST MECHANICAL DIGESTION happens Muscles in the stomach mix the food around Pepsin (an enzyme that speeds up protein digestion) and stomach acids are mixed in and break most of the solid pieces into mush So some chemical digestion happens too Sphincter….one way valve

SMALL INTESTINE….Absorption This is where MOST CHEMICAL DIGESTION happens Liver and Pancreas help It is 6m (or ______ft long) and covered with villi that increase the surface area for absorption even more Food is absorbed as the useable molecules here Blood vessels in the villi transport the nutrients to all cells in the body

Liver and Pancreas The LIVER is the largest organ inside the body. Liver makes BILE. Gallbladder stores bile. Bile breaks fats. The PANCREAS produces enzymes that flow into the small intestine and help digest starches, proteins and fats into usable molecules **Bile isn’t an enzyme, it doesn’t digest anything. BUT…..it does break BIG FAT particles into little fat particles………………………………………

Large Intestine PERISTALSIS is the involuntary muscles movements pushing digested food through the digestive tube. (One way only) By the time digested material makes it to the Large Intestine, most of the nutrients have been absorbed and only water and fiber are left. Water is absorbed and the remaining material is “eliminated” About 1.5 m (3 feet long) and wider than the ‘small’ intestine. http://stream1.gifsoup.com/view1/4272400/digestion-large-intestine-o.gif

End of Chapter Review assignment Text page 73 Write out the statement finishing with the correct answer Multiple choice #1,3,4,5 Modified true false # 6,7,9,10 Text page 74 Write answers in complete sentences to # 11,12,14,15, and16. TEST on Chapter 2….Soon…..be ready! Study vocab and be sure to review!