Download DIGESTIVE AND EXCRETORY SYSTEMS

DIGESTIVE AND
EXCRETORY SYSTEMS
The digestive system takes
the food a person eats,
breaks it down into tiny
particles, and absorbs the
important nutrients and
water.
The salivary glands,
tongue, and teeth are
part of the
mechanical digestion
system.
The organs of the
chemical digestive system
are automatic, meaning
they are controlled by the
brain, with no conscious
control by the person.
There are several
organs that
combine to make
the digestive
system.
They include the
stomach, pancreas,
liver, gall bladder,
spleen, and the large
and small intestines.
LIVER STOMACH
INTESTINES
LARGE
SMALL
BLADDER
GALL BLADDER
As chewed food heads
for the stomach, it
travels in a long,
smooth tube called the
esophagus.
The esophagus is
located in the throat
behind the trachea,
which is the tube that
carries oxygen to the
lungs.
The esophagus consists of
rings of muscles that
contract in a series of
waves called peristalsis,
which moves food down
the esophagus to the
stomach.
esophagus
stomach
The stomach is a small
sac that can hold over
four quarts of food. It can
easily expand to 50 times
its empty size.
Although the stomach
appears smooth on the
outside, the inside
consists of many
ridges.
These ridges help move
the food slowly back and
forth in a wave-like
effect, causing it to break
up into smaller and
smaller pieces.
The sphincter is a
muscle located where
the stomach meets
the esophagus.
ESOPHAGUS
ESOPHAGEAL
SPHINCTER
STOMACH
The sphincter muscle
contracts and closes so
the stomach contents do
not go back up the
esophagus.
The diaphragm
stimulates the stomach
to release extremely
powerful hydrochloric
acid secretions.
This acid along with an
enzyme called pepsin,
breaks food into protein
and then into simple
amino acids that the body
can absorb.
The acid would be strong
enough to actually burn holes
through the lining of the
stomach if the stomach did
not constantly replace
destroyed cells with new
ones.
People who develop certain
types of ulcers have areas
where the cells are not
replaced fast enough to
prevent the tissue of the
stomach lining to be
damaged.
These secretions
mix with the food
and turn it into a
liquid called
chyme.
Once it leaves the
stomach as a
liquid, food enters
the small intestines.
3 parts of small intestines
• duodenum
• jejunum
• ileum, which empties into
the large intestines
duodenum
jejunum
ileum
Muscle contractions
force the food along
its 15 - 20 foot
length.
As it travels through the
small intestines, the
food mixes with special
digestive juices called
enzymes
Lining the small
intestines are
millions of
microscopic hairs
called villi
After all the nutrients have
been removed from the
food by the villi, the food
exits the small intestines
and enters the large
intestines.
It is shorter than the small
intestines with a length of
only 5 feet,it is called the
large intestines because its
diameter is much larger.
The large intestines
is divided into 6
sections.
liver
gallbladder
spleen
stomach
large
intestines
small
intestines
The top section, called the
cecum, is where the small
fingerlike projection
called the appendix is
located.
There appears to
be no known use
for the appendix.
In the large intestines all the
moisture left within the food
is absorbed and a hard waste
product is passed along its
length until it is removed from
the body through the rectum.
The liver is a large
reddish-purple organ
that sits on the right
side of the body,
directly under the
diaphragm.
Blood passes
through the liver
to be filtered.
The liver contains
about 10 percent of
the body’s total
blood supply.
The liver has
over 500 known
functions.
Among these are to filter
poisonous materials from the
blood, store glycogen, make
carbohydrates and fat, and
store vitamins, including
vitamin D which is needed for
blood clotting.
The liver also produces bile
that it releases into the
small intestines to aid
digestion and controls the
temperature of blood.
Hepatitis is a
disease of the
liver.
The gall bladder is a
small sac that is only
about 3 inches long and
an inch wide. It is
located under the liver.
It serves as a reservoir,
or storage area for extra
bile that the liver has
produced.
The gall bladder
empties into the
small intestines.
LIVER
GALL BLADDER
The spleen is a flat,
oblong organ
wrapped around
the stomach.
Its function is to
remove diseaseproducing bacteria
and worn-out red
blood cells.
S
P
L
E
E
N
It also produces
antibodies and a
variety of blood
cells.
A person can function well
without a spleen. They are,
however, at a greater risk of
catching certain diseases and
infections.
The pancreas is located
in the center of the
upper abdomen, behind
the stomach and the
small intestines.
It not only produces
enzymes to help break
down food, but it more
importantly produces
insulin which helps to keep
the blood sugar level in
balance.
When the pancreas
malfunctions, a
disease called
diabetes results.
The kidneys and
bladder are part
of the excretory
system.
kidney
ureter
bladder
urethra
The job of the
excretory system is to
remove carbon
dioxide, nitrogen,
heat, and water.
Located near the
vertebrae are a pair of
small bean-shaped
organs called the
kidneys.
Their function is to
filter blood and
remove the waste
products.
They produce about 3
pints of urine and filter
about 47 gallons of
blood per day.
The bladder is a sac-like
organ that holds urine
sent from the kidneys
until it is removed from
the body.