Download The Digestive System

The Digestive System
By Matt Francis
Mouth
The mouth has many functions,
but the three main digestive
functions are the intake of food,
the beginning of mechanical
digestion, and swallowing. The
mouth is also the beginning of
chemical digestion. Saliva breaks
down food chemically using
enzymes while teeth break food
down mechanically by chewing.
An unusual fact is the average
person chews their food 14.235
times before swallowing.
Esophagus
The tube connecting the throat to
the stomach. It is 10 to 12 inches
long in adults and 3/4 inches
wide. It is coated with mucus and
surrounded by muscles that push
food down by contracting in
waves. Its function is to transport
food from the throat to the
stomach and keep stomach
contents in the stomach.
An interesting fact is since the
esophagus uses muscle
contractions to move food to the
stomach, food could get to a
person’s stomach even if they
were standing on their head.
Stomach
Food undergoes both mechanical
and chemical digestion in the
stomach. The stomach churns the
food using muscular contractions
which eventually turns the food
into a liquid called chyme. The
stomach then releases gastric
juices to break down the food
particles in the chyme. The
stomach’s 3 main functions are to
store food we swallow, to break
down large fat and protein
molecules in the food, and to
empty partially digested chyme
into the duodenum.
An interesting fact is an adult’s
stomach can hold 1.5 liters of
material.
Liver/Gallbladder
The liver’s main function in
digestion is making a chemical
called bile that will be mixed with
food. But, bile is not stored in the
liver. It is stored in the
gallbladder. The gallbladder mixes
bile with chyme in the duodenum
and breaks down large fat
particles in the chyme.
An interesting fact about the
liver is it is the second largest
organ in the body, behind skin. An
interesting fact about the
gallbladder is bile that stays in the
gallbladder longer becomes more
potent.
Pancreas
The pancreas has two main
functions in the digestive system.
It mixes a digestive solution in
with the chyme which breaks
down carbohydrates, proteins,
and fats. It also neutralizes
stomach acid. The pancreas also
makes insulin, a hormone that
lets glucose pass from the
bloodstream into your cells.
An interesting fact is because of
the pancreas’ location, it is a hard
organ to injure.
Small Intestine
Most of the digestion takes place
in the small intestine. Chemicals
from the liver and pancreas are
mixed with the chyme and break
food particles down. Absorption
of food takes place here. Small,
fingerlike projections called villi
absorb nutrients into the
bloodstream.
An interesting fact about the
small intestine is it is 22 feet long.
Appendix
The appendix is usually 2 to 20
centimeters long and 7 to 8
millimeters wide. It is located at
the right lower end of the
abdomen. The appendix has no
known function.
Large Intestine
The main function of the large
intestine is to remove the water
from the chyme. This helps keep
water in your body. The chyme
may stay there for as long as
three days. After water is
absorbed, the material becomes
more solid. It is about 1.5 meters
long and 10 centimeters wide.
An interesting fact about the
large intestine is it has 6 parts.
Rectum/Anus
The rectum and anus are the final
stages of the digestive tract. The
rectum and anus use muscular
contractions to push the waste
out of the body. The rectum
provides temporary storage for
the waste until it is expelled out
of the anus.
An interesting fact about the
rectum is it is the last straight
portion of the large intestine. The
anus is not apart of the large
intestine.
Systems That Work With the Digestive System
The circulatory system works with the digestive system by the blood
transporting nutrients from the food. The excretory system works with it
by expelling wastes. It also works with the muscular system using the
muscular contractions.