The Digestive System and Nutrition

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The Digestive System and Nutrition

• 7th Grade Health

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Important Vocabulary

• Digestion The process of breaking food down to
  be used by the body.
• Why is digestion important?
• Food must be broken down in order for our body to
  be able to absorb all of the substances important
  for daily functions.
• Food must be small enough to be absorbed into the
  blood and carried to the cells.

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Important Vocabulary

• Digestion cont
• Two types of digestion
• Mechanical Digestion occurs in the mouth
  (chewing), and in the stomach (churning of
  stomach muscles)
• Chemical Digestion occurs through the use of
  enzymes (substances which chemically act on food
  to break it down) in saliva, the stomach, in the
  small intestine

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Important Vocabulary Organs of the Digestive
System

• Mouth The first step in digestion is actually
  getting the food into your body.
• Teeth mechanically break food down into smaller
  pieces
• Saliva softens food and chemically breaks food
  down further
• Tongue moves food around the mouth, forms a
  bolus (ball of food)

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Important Vocabulary Organs of the Digestive
System

• Esophagus a hollow tube at the back of the
  throat that connects to the stomach.
• To prevent food from going down the wrong pipe
  a flap of skin called the epiglottis closes over
  the opening of the trachea (windpipe) when we
  swallow
• Peristalsis muscular contractions that move
  food down the esophagus into the stomach.
• Imagine squeezing a tube of toothpaste

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Important Vocabulary Organs of the Digestive
System

• Stomach a hollow, J-shaped organ located below
  the esophagus and above the small intestine.
• The stomach uses both mechanical and chemical
  digestion to break food particles down.
• Mechanical digestion 3 layers of muscles
• Chemical digestion digestive or gastric enzymes

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Important Vocabulary Organs of the Digestive
System

• Small Intestine responsible for absorbing
  nutrients from food.
• First 1/3 of the S.I. Bile from the gall bladder
  and digestive enzymes from the pancreas and walls
  of the small intestine further break food down.
• Second 1/3 of the S.I. contains finger-like
  projections called villi

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Important Vocabulary Organs of the Digestive
System

• Small Intestine cont
• Villi increase the surface area of the S.I. so
  that more nutrients can be absorbed into the
  blood stream

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Important Vocabulary Organs of the Digestive
System

• Large intestine large because it is wider in
  diameter than the small intestine (about 3 vs.
  1). Responsible for absorbing water from
  undigested food.
• Material found in the large intestine is mostly
  food that cannot be digested any further and
  water.

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Important Vocabulary Organs of the Digestive
System

• Large Intestine 3 parts
• Colon Absorbs water and nutrients from food, as
  the material moves through the colon it gets
  harder and harder-turning into feces.
• Rectum Stores feces. Feces move to the anus by
  peristalsis.
• Anus Eliminates solid waste from the body

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Other Organs

• Liver produces bile, is located to the right of
  the stomach.
• Bile responsible for breaking down fats
• Pancreas located behind the stomach, and above
  the small intestine.
• Secretes digestive enzymes
• Gall Bladder stores and excretes bile

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Some videos to use

• http//www.youtube.com/watch?vZ7xKYNz9AS0
• http//kidshealth.org/kid/htbw/_bfs_DSmoviesource.
  html
• http//www.youtube.com/watch?vq3986Yfl5cU
• http//kitses.com/animation/swfs/digestion.swf

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http//kitses.com/animation/swfs/digestion.swf
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http//kitses.com/animation/swfs/digestion.swf
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http//kitses.com/animation/swfs/digestion.swf
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http//kitses.com/animation/swfs/digestion.swf
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http//kitses.com/animation/swfs/digestion.swf
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http//kitses.com/animation/swfs/digestion.swf
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http//kitses.com/animation/swfs/digestion.swf