Transcript The Digestive System

The Digestive System
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Digestive functions
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Breaking down substances
The mechanical breakdown of
food into smaller pieces is called
physical digestion.
This process occurs:
 by chewing food in the mouth
 by squeezing in the stomach.
What is the purpose of physical digestion?
 Smaller pieces of food will pass more easily through
the alimentary canal.
 Smaller pieces of food will provide a greater surface
area for enzymes to break down the substance further.
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From the mouth to the stomach
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From the small intestine to the blood
Physical digestion continues in the stomach as it squeezes
its contents into the small intestine.
glucose
Here, the digested
particles are absorbed into
the blood to be taken
elsewhere in the body.
Only smaller molecules, such
as glucose, are able to diffuse
from the small intestine,
through the villi, and into the
blood, moving from higher to
lower concentration.
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Enzymes in the body
Enzymes catalyze thousands of reactions that need to
take place in order to maintain life. What are some of
these reactions?
 respiration
 protein synthesis
 digestion.
Digestive enzymes break down
large food molecules into smaller
molecules so they can be
absorbed into the blood. This is
called chemical digestion.
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Enzymes of digestion
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Further breakdown of starch
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