Final Digestion and Absorption

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Final Digestion and Absorption

• By Mrs. Tilicki

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The Digestive Process

• Yesterday, you learned that digestion starts in
  the mouth where saliva and teeth start the
  processes of digestion.
• Next food spent about 10 seconds in the
  esophagus,
• And then moved into the stomach where it was
  prepared for absorption.
• You also learned that some of the process was
  mechanical and some of it was chemical.

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The ticket taker!

• Now that your food is in your stomach, it will be
  changed into a thick liquid.
• This thick liquid will slowly be released into
  the rest of the digestive system.

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The Small Intestine

• This is where most of the chemical digestion
  takes place.
• The small intestine is only about 2 or 3
  centimeters wide. Half the width of the Large
  Intestine.
• The starches and proteins have been broken down,
  and now the fats are left.

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Small Intestine

• Almost all chemical digestion and absorption of
  nutrients takes place in the small intestine.
• Enzymes and secretions produced in the small
  intestine, liver, and the pancreas mixes with the
  liquid sent to the small intestines from the
  stomach.
• The liver and the pancreas send their substances
  through to the small intestine through tiny tubes.

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The Liver

• The liver is in the upper section of the abdomen
  and is the heaviest organ in your body. It is a
  chemical factory that breaks down medicine and
  other substances and keeps nitrogen out of your
  body.
• It produces bile and bile is really important for
  breaking down fat substances.

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Gallbladder

• The bile flows from the liver into the
  gallbladder, the organ that stores bile.
• After you eat, bile goes through the gallbladder
  into the small intestine.
• Bile is not an enzyme and does not break down
  food.
• It does break up large fat particles into smaller
  fat droplets. These are broken down in the
  pancreas.

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The Pancreas

• The pancreas is a triangular organ that is in
  between the stomach and the beginning of the
  small intestine.
• The pancreas produces enzymes that break down
  starches, proteins, and fats.
• The pancreas cannot break down fiber.

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Absorption in the Small Intestines

• Now that everything is broken down, it is ready
  to be absorbed.
• Inside the small intestine are little finger like
  structures called villi. There are little blood
  vessels in them and nutrients can pass through
  the cells here and get into our blood vessels.

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Villi

• The villi help the small intestine by getting the
  digested food faster than if the lining was
  smooth.

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The Large Intestine

• By the time the materials reach the end of the
  small intestine, most of the nutrients have been
  absorbed.
• Now it moves into the large intestine. The large
  intestine is about 1 ½ meters long!
• There are bacteria that live in the large
  intestine and they feed on the material passing
  through.

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Bacteria In the Large Intestine

• The bacteria are not harmful.
• They are helpful because they form vitamin K and
  other vitamins.
• The material left in the large intestine contains
  water, undigested food, and fiber.
• The water is removed and the remaining materials
  are ready to be eliminated from the body.

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The end of digestion

• The large intestine ends in a short tube called
  the rectum.
• Waste is made into solid form and compressed.
• It is eliminated through the anus, a muscular
  opening at the end of the rectum.