Download How your body uses food

How Your Body Uses
Food
Digestion
Digestion
• The process of
breaking down
food into usable
nutrients
The Mouth
• Digestive process
begins even before
you eat
• Just smelling and
seeing can start
saliva flowing
• Saliva is the first
of many digestive
juices that act on
food to break it
down
The Mouth
• Food is broken down physically
by teeth
• Food mixes with saliva and
makes it easier to swallow and
digest
The Esophagus
• A long tube
connecting the
mouth to the
stomach
• Muscles
contract and
relax forcing
food into the
stomach
The Stomach
The Stomach
• Widest part of the digestive
system
• Muscular pouch located on the
left side of your body inside
the rib cage
• On average your stomach can
hold about 4 cups of food
The Stomach
• Walls manufacture gastric juices
– A combination of acid and enzymes
that helps in the chemical breakdown
of the food
• Food is churned until it turns into a
thick liquid called chyme (KIME)
• Chyme is released into the small
intestine a little at a time
The Stomach
• Different foods take different
amounts of time to break down and
leave the stomach
• Carbohydrates take the shortest
amount of time
– Usually 1-2 hours
• Proteins take longer
– 3-5 hours
• Fats take the longest
– Up to 7 hours
The Small Intestine
• Small winding
tube between the
stomach and the
large intestine
• Chyme is acted by
three types of
digestive juices
– Bile
– Pancreatic Juice
– Intestinal Juice
Bile
• Substance that
helps your body
digest and
absorb fats
• Produced in the
liver
• Stored in the
Gall Bladder
until needed
Pancreatic Juice
• Contains enzymes
that help break
down
carbohydrates,
proteins, and fats
• Produced by the
Pancreas
– A gland connected
to the small
intestine
Intestinal Juice
• Produced in the small intestine
• Works with other fluids to
break down food
The Small Intestine
• When broken down, carbohydrates
are turned into a simple sugar
called glucose
– Body’s basic fuel supply
• Fats are changed into fatty acids
• Proteins are broken down into
amino acids
• Vitamins, minerals, and water do
not need to be broken down
– They are ready for action just as they
are
Digestion Video
• The Stages of Digestion
• http://www.youtube.com/watch?v
=A7jKCfx0Mo&eurl=http%3A%2F%2Fvideo.
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ure=player_embedded
Using Nutrients
• Once food has been broken
down into nutrients, digestion
is complete
• You body still has work to do
though
• It must absorb the nutrients
and take them to where they
can be used or stored
Absorption
• Nutrients are absorbed into the
bloodstream
• Most absorption takes place in
your small intestine
Processing and Storing
Nutrients
• After absorption, nutrients are
carried through a blood vessel
called the portal vein to the liver
• One of the livers jobs is to turn
nutrients into forms the body can
use
– Example:
• Converts amino acids into different kinds of
proteins
• The proteins are then carried by the blood to
where they are needed
Processing and Storing
Nutrients
• If not needed immediately
nutrients are stored
– Example:
• Extra glucose is converted by the
liver into glycogen
• Stored in the liver and in muscles
• If there is more than can be stored it
is converted to body fat
– Fats are then deposited throughout the
body as and energy reserve
Processing and Storing
Nutrients
• Minerals are stored in various
ways
– Some examples:
• Iron is stored in the liver and bone
marrow
• Fat-soluble vitamins are stored
mainly in the liver and body fat
Quiz
• How do nutrients get from the
digestive system to the
bloodstream?
• Name two ways in which excess
glucose can be stored.
• Sketch a design for a poster or
bulletin board showing how food is
broken down into nutrients and
how nutrients travel through the
body.