2. The digestive system is
made of hollow organs
joined in a long, twisting
tube from the mouth to the
anus—and other organs
that help the body break
down and absorb food.
Functions:
Ingestion
Digestion
Absorption
Elimination

3. or to eat The first activity of the digestive system
is to take in food
through the mouth.
This process, called
ingestion, has to take
place before anything
else can happen.

4. or to break down Digestion begins in the mouth with
mechanical (physical digestion).
Teeth helped by the tongue and lips
(cut, tear, chop, grind and push)
chew the food;
at the same time salivary glands
produce enzymes (chemical
digestion) in saliva to help
break down food and swallow.
The Human mouth
can make up to three
pints of saliva a day.

5. The food is pushed to the pharynx (throat).
Then into the esophagus (food tube); a
smooth muscle that contracts automatically
to push the food into the stomach.
Digestion continues with churning and
mixing actions in the stomach which
produces a soup like mixture called chyme.
The chyme then goes into the small
intesitne.
The average human stomach holds about 48 ounces of
food matter. Food stays in the stomach for two to three
hours before it is emptied into the small intestine.

6. Absorption is when nutrients pass through the cell membrane in the
small intestine into the blood or
lymph capillaries.
The liver produces a substance called bile,
which is stored in the gall bladder and then
squeezed out into the intestine. Bile goes to
work on the fat in foods, dissolving it into a
liquid the body can digest.
The average human small intestine is about 1.5
to 2 inches wide. If you stretched it out, it would
measure about 22 feet in length.

7. or to remove The food molecules that cannot be
digested or absorbed move into the large
intestine where water is absorbed. Feces
(brown solid waste) is then stored in the
rectum briefly.
Elimination or defecation is the removal
of indigestible wastes (feces) through the
anus.

8. Large Intestine According to a study from the Stanford
University School of Medicine, there are
more than 5,800 different species and strains of
bacteria in the human colon (large intestine).
Most of them are benign or even beneficial. Some
of them provide nutrients like vitamin K, and
others keep the bad bacteria under control.

9. A Foods Tale Digestion of food begins in the mouth, with mechanical
breakdown of ingested material
by chewing with your teeth.
Additionally, food in the mouth is
mixed with saliva, which
contains a digesting enzyme,
known as amylase. This begins
the chemical breakdown of food
better known as chemical
digestion. After chewing, food is
swallowed down the pharynx
(throat), and enters the
esophagus.

10. A Foods Tale The esophagus is a tube to transfer ingested
material from the mouth to
the stomach – very little, if any,
breakdown of food occurs in the
esophagus.

11. A Foods Tale Food then passes into the stomach, where it is exposed
to acid, and additional
enzymes promote protein
and fat breakdown.

12. A Foods Tale Next, food passes into the small intestine, where
additional enzymes from
the liver and pancreas are
secreted and mixed with
food, to further break
down protein and
carbohydrates, and to
emulsify fats. Additionally,
food absorption occurs in
the small intestine. If
breakdown of ingested
material and absorption do
not occur normally symptoms
of food intolerance result
(diarrhea or constipation).

13. A Foods Tale Finally, food passes into the
large intestine, where excess
water is absorbed, and water is
stored in the form of feces.
Food can stay in the large
intestine for a long time, up to
96 hours! Very little in the way
of nutrients is absorbed by the
colon – if absorption hasn’t
occurred in the small intestine,
those leftover nutrients will be
broken down by the bacteria in
the colon.

14. A Foods Tale The solid parts of the food which have not
been absorbed are
stored in the rectum.
When the rectum is full,
the remains of the food
are passed out (eliminated)
of the body through the
anus.