Digestion Lab We are going to use household items to model the digestive system.
Digestion Lab Substances in food that provide raw materials and energy the body needs to live Our digestive system turns the chemical energy in these nutrients into energy we can use
Digestion Lab Procedure 1. Label four plastic sealable bags with the following: protein (lunchmeat) vegetable (lettuce) starch (crushed cracker) dairy (cheese)
Digestion Lab Procedure 2. Use a cotton swab to lightly coat the inside of the bag with vaseline. 3.Measure out 60 mL of vinegar in a graduated cylinder and pour into the bag
Digestion Lab Procedure 4. Add 1 drop of food coloring to one side of the bag so the drop slides down the vaseline. 5.Using the balance, mass 10 g of your groups food item. 6. Add the 10 g of food to the correct bag and seal.
Digestion Lab Procedure 7. Shake the sealed bag from side to side 50 times. 8. Compare each bag and make an inference about how fast each is “digesting” 9. At the end of the period, make sure the bags go in the trash.
Digestion Lab Questions. Write these answers in your spiral: 1.Which food type was digested the fastest? ______________________ 2. Which food type needed more digesting time? _________________
Digestion Lab Questions. Write these answers in your spiral: 3. What did the plastic bag represent in this model?______________________ 4. What did the vaseline represent in this model?__________________________
Digestion Lab Questions. Write these answers in your spiral: 5. What did the vinegar represent in this model?______________________ 6. What is at least one limitation of this model? _________________________
Stomach and Intestine Slides Now using the microscopes. Look at the slides labeled stomach and small intestine. In your spiral, diagram what you see.
Organs of the Digestive System MouthRectum EsophagusAnus StomachPancreas Small intestineGall Bladder Large intestineLiver
Functions of the Digestive System Digests food into molecules the body can use (physical or chemical change) Absorbs nutrient molecules and carries them around the body (physical change) Eliminates waste material from unused nutrients
Digestion body breaks down food into small nutrient molecules –mechanical –chemical
Mechanical Digestion Food is physically broken down into smaller pieces Begins in the mouth –Teeth chewing/tearing –Movement of smooth muscles
Chemical Digestion Chemicals produced by the body break foods into their smaller nutrients –mouth –stomach
Absorption Process by which nutrient molecules pass through the wall of your digestive system into your blood –The lining of the small intestine is covered in villi that aid in absorption
Elimination Materials that are not absorbed leave the body as waste The waste material left over after food is digested must leave the body to prevent illness
Which is not a function of the digestive system? a)Breaking down food into molecules the body can use b)Absorbing food molecules into the blood to deliver to the body c)Changing waste into molecules the body can use d)Eliminating undigested waste from the body
Mouth Digestion begins in the mouth –Mechanical – teeth –Chemical- saliva
Esophagus Muscular tube that connects your mouth to your stomach –moves food down into your stomach using involuntary muscle contractions (peristalsis) –Lined with mucus that allows food to slide down
The Stomach J-shaped muscular pouch Most mechanical digestion takes place in the stomach Chemical digestions also takes place –Stomach secretes digestive juice (enzymes) that break down food Average adult stomach holds 2 liters Mucus keeps the acids from burning a hole in your stomach
Modeling Place the marble in the end of the tube and squeeze it down into the balloon.
Modeling What do you think this could be a model of? –What is the tube? –What is the balloon? –What is the marble? –What is the soap? esophagus stomach food saliva and mucus
Which is not an example of mechanical digestion? a)Teeth chewing food b)Tongue breaking up food c)Smooth muscles in stomach churning food d)Hydrochloric acid breaking down proteins
Small Intestine Where most of the chemical digestion takes place Where most of the absorption takes place Covered in villi which enlarge the surface area
a)Most digestion happens here. b)Intestinal juice (full of enzymes) breaks down food. c)Digestive Helpers Liver, Gall bladder, Pancreas d)Digested food is absorbed through the villi into a network of blood vessels that carry the nutrients to all parts of the body. e) By the time food leaves the small intestine, it is empty of all nutrients except water. Small Intestine
The villi increase the surface area that can absorb nutrients
Where does most digestion take place? a)Mouth b)Stomach c)Small intestine d)Liver
Liver Breaks down medicines and other chemicals Produces bile that breaks up fat particles The gall bladder stores bile
Pancreas Produces enzymes that flow into the small intestine Secretes insulin Causes diabetes when it does not make insulin
Large Intestine Last section of the digestive tract Food spends 18-24 hours here Where water is absorbed Vitamins B & K are made by bacteria in the large intestine
Rectum and Anus Rectum – end of the large intestine, forms the solid waste –elimination Anus – muscular opening at the end of the rectum –elimination
Which cell parts are like the digestive system? Which one makes energy? Which one helps get rid of waste? mitochondria lysosomes Which one allows materials to pass in and out? cell membrane
The Digestive System Interacts with: muscular system (smooth muscle) to move and digest food respiratory system to provide oxygen circulatory system to move nutrients