Download Your Digestive System

Your Digestive System
The main role of the digestive
system is to break down and
absorb nutrients that are necessary
for growth and maintenance.
The Path of Digestion
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Mouth
Esophagus
Stomach
Small intestine
Large intestine
Rectum
Helpers are: liver,
gall bladder &
pancreas
Beginning in the Mouth
 Mechanical
Digestion begins:
– Chewed by the mouth using teeth and
tongue
– Food is swallowed & squeezed
through the esophagus to the
stomach
– Churned by stomach muscles
Swallowed food enters the Esophagus
http://www.endoatlas.com/atlas_es.html
Esophagus
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Moves food from the back of throat to
the stomach
Epiglottis – flap of skin that covers
windpipe (trachea), keeping food out of
lungs
Valve at the end of the esophagus
(sphincter) allows food to pass into the
stomach but not back into the
esophagus
Takes 8-10 seconds to move bolus
(chewed food) from swallowing to
stomach
From the esophagus to the Stomach
Click on picture to show video
http://www.gastrointestinalatlas.com
Stomach
Muscular walls of stomach contract to
churn and mix the food with gastric
juices
 Gastric juices (hydrochloric acid and
pepsin with mucus) - begin the break
down of proteins
 Chemical and mechanical digestion
takes about 2 to 3 hours
 Mixture of partially digested food is
called chyme
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Food passes through the pyloric valve from the
stomach to the small intestines
Close-up of pylorus
(pyloric valve)
The small intestine is
22 feet long
Small Intestine
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Chyme is flooded with enzymes
Enzymes help break down the nutrients
to basic forms
Liver produces bile (stored in the gall
bladder) – a salt that helps break down
fats
Villi - finger like projections in the wall
of the small intestines where blood
vessels absorb nutrients into the
bloodstream
From the small intestine food passes through a
valve to the large intestine
Click on
picture to
show
video clip
http://www.gastrointestinalatlas.com
Large Intestine
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Undigested material (fiber, water, and
un-digestible substances) moves into
the large intestine or colon
Water is removed and undigested
material reduced to a solid waste called
feces
Colon contains bacteria to help final
digestion
Feces (yes, poop) is stored in the
rectum and eliminated
Elimination
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Undigested waste is
moved into the rectum
where it is eliminated
through the anus
Peristalsis – the
muscular contractions
that move food through
your digestive system
The Liver (& Gall Bladder)
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Liver produces bile to help with chemical
digestion
Bile stored in the gall bladder (then sent
to beginning of small intestine)
The liver filters harmful substances or
wastes, turning some of the waste into
more bile
The liver helps figure out how many
nutrients will go to the rest of the body,
and how many will stay behind in storage.
– For example, the liver stores certain vitamins
and a type of sugar your body uses for energy.
Pancreas
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Produces some
digestive enzymes
Chemical Digestion
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Mouth - chemical digestion begins in the
mouth with saliva (spit)
Stomach - gastric juices (stomach acid, mucus,
enzymes) begin to break down the food to
smaller molecules
Small intestine – food broken down even more
so your body can absorb the nutrients
** Most digestion occurs in the small intestine
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Large intestine – bacteria help with final stage
of digestion
Nutrients
Carbohydrates: starches and
sugars
 Proteins: simplest form is amino
acids
 Fats : absorbed as fatty acids (with
the help of bile from the liver)
 Vitamins & Minerals
 Water
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Enzymes
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Enzymes are proteins that help
chemical digestion
Enzymes help a chemical reaction
without being changed itself
Found in raw fruits and vegetables
Also produced in the stomach,
small intestine and pancreas
Click here to link to KidsHealth flash player of digestive system.
http://kidshealth.org/kid/body/digest_SW.html
Click here to link to animation of food being swallowed
http://www.innerbody.com/anim/mouth.html