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Digestive Systems
Biology 30
Shelby and Kendall
Sponge
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A sponge has no
digestive system.
They feed by drawing
water through their
bodies, then filter out
the tiny particles,
which they then
digest.
Earthworm
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
Dirt contains plant and animal matter, which the
earthworm eats and then eliminates the rest.
Its digestive system consists of the following:

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An esophagus for the food to go down
A crop to store the food in
A gizzard that grinds the food down
Intestines for the food to pass through and take out
nutrients
An anus for the food to come out
Frog

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Their digestive system begins with
their mouth, they use their maxillary
teeth which are located along the
upper jaw to break down food before
swallowing. It uses its tongue to catch
the food.
The food then moves through the
esophagus into the stomach.
The food then proceeds to the small
intestine where most digestion occurs.
Frog
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They carry pancreatic juice from the pancreas,
and bile through the gallbladder from the liver
to the small intestine, where the fluids digest
the food and remove the nutrients.
When the food passes into the large intestine,
the water is reabsorbed and wastes are routed
to the cloaca.
All wastes leave the body through the cloaca.
Human
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The stomach has three tasks. First, it stores the
swallowed food and liquid. To do this, the
muscle of the upper part of the stomach relaxes
to accept swallowed substances. The second job
is to mix up the food, liquid, and digestive juice
produced by the stomach. The lower part of the
stomach mixes these materials. The third task
is to empty its contents slowly into the small
intestine.
As the food dissolves into the juices from the
pancreas, liver, and intestine, the contents of
the intestine are mixed and pushed forward to
allow further digestion.
Human
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A human’s digestive system is made
up of a digestive track.
Organ walls move and push food
and liquid through the system and
also mix the contents within each
organ. Food moves from one organ
to another through muscle action
called Peristalsis.
The muscle of the organ shrinks to
create a thin area and then pushes
the thinned portion down the length
of the organ. This pushes the food
and fluid in front of them through
each empty organ.
Human
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The first major muscle movement
happens when food or liquid is swallowed.
Once the swallow begins, it becomes
uncontrolled and continues under the
control of the nerves.
Swallowed food is pushed into the
esophagus, which connects the throat
above with the stomach. At the junction of
the esophagus and stomach, there is a
ringlike muscle, called the lower
esophageal sphincter, closing the passage
between the two organs. As food
approaches the closed sphincter, the
sphincter loosens and lets the food pass
through to the stomach.
Human

Finally, the digested nutrients are absorbed
through the intestinal walls and moved
throughout the body. The waste products of this
process include undigested parts of the food,
known as fiber. These materials are pushed into
the colon, where they remain until the feces are
expelled by a bowel movement.