Digestion and Absorption

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Digestion and Absorption
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Digestion

• Digestion-The bodily process of breaking food
  down into simpler compounds the body can use.
• The Digestive Tract- a tube, about 30 feet, that
  extends from the mouth to the anus. It contains
  the esophagus, the stomach, and the small and
  large intestine. These parts work together to
  both mechanically and chemically help the body
  use food.

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The Digestion Process

• 2 phases- Mechanical and Chemical
• Mechanical- Begins in the mouth.
• 1.Teeth chew and break down food.
• 2.Contractions of the muscular walls of the
  digestive tract carry on the mechanical action.
  These contractions mix food particles and break
  them into smaller pieces.
• 3.Waves of contraction, peristalsis, the muscles
  push food through the digestive tract.
• Emotions such as sadness, depression and fear
  can slow this process down. Anger and aggression
  can speed up this process.

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The Digestion Process

• Chemical Phase-
• Also begins in the mouth. As you chew food is
  mixed with saliva, an enzyme-containing liquid.
  Saliva moistens the food partials and begins to
  break down starches.
• In the stomach, gastric juices containing
  hydrochloric acid are secreted. These juices
  break down food further. Carbohydrates leave
  the stomach first, Proteins are second, followed
  by fats. As a result you will feel hungry sooner
  after a meal high in Carbs.

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The Digestion Process

• 3. Next the food leaves the stomach and enters
  the small intestine. Here several juices
  intestinal, pancreatic, and bile break down the
  food.
• 4. Then indigestible residues, bile pigments,
  other waste and water travel into the large
  intestine. The large intestine acts as a storage
  area. Eventually the body will excrete these
  material in the feces.

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The Absorption Process

• The body can absorb water, ethyl alcohol, and
  simple sugars directly from the stomach. They
  pass through the stomach walls and into the
  bloodstream. However, most absorption takes place
  in the small intestine through capillaries.