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Digestive System

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					Digestive System
         The Digestive Process
• During digestion, food is broken down into
  forms that the body can use.
• This breaking down process involves both
  physical and chemical changes in the food.
         What is physical change?
• It is a change in the physical properties of a
  substance.
  – Ex: shape, size color, and odor.
      What is chemical change?
• It is a change in the chemical properties of a
  substance, which results in a new substance.
  – Ex: burning of wood, rusting of a nail
         The Digestive Process
• All of your food is made up of 1 or more
  nutrients.
  – Ex: proteins, carbohydrates, fats, vitamins, and
    minerals
• Vitamins and minerals can directly pass from
  the digestive system into the body without
  undergoing a chemical change
• Carbohydrates, proteins, and fats must be
  broken down into smaller, usable forms.
           Mechanical digestion
• Is physical break down of food into small pieces.
• Mechanical digestion breaks large pieces of food
  into smaller ones
  – Ex: What would happen if you tried to swallow a
    whole cracker?
             Chemical Digestion
• Is where large food molecules are broken down
  into smaller molecules.
  – Ex: a cracker is made mostly of starch, which is a
    carbohydrate and must be broken down into more
    simpler sugars called glucose

				
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posted:7/18/2013
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