Digestive System
Chapter 16 Section 3
Final Digestion and Absorption
Tuesday, May 17, 2011
Small Intestine
The small intestine is the part of the digestive
system where most of the chemical
digestion and absorption takes place.
It is called the small intestine because of the
diameter, not the length. It is about 6 meters
long.
By the time food reaches the small intestine
it has become a thick liquid that needs to be
digested.
Starches proteins and fats are digested in
the small intestine.
Enzymes form the live, gall bladder and
pancreas enter the small intestine and aide
in chemical digestion.
Tuesday, May 17, 2011
Small intestine Absorption
The small intestine has
small structures called
villi which make it well
suited for absorption.
Villi help to increase
surface area. The extra
surface area allows for
greater absorption.
Blood vessels in the villi
allow nutrients to enter
into the bloodstream
for transport.
Tuesday, May 17, 2011
Liver and Gall Bladder
The liver is located in the upper
abdomen an is the largest and heaviest
organ in the body.
Besides breaking down medicines and
eliminating nitrogen, the liver produces
bile which breaks down fats(lipids).
Bile flows from the liver and is stored in
the gall bladder.
Bile is an enzyme and does not
chemically digest food. It breaks fats into
smaller molecules which are chemically
broken down in the pancreas.
Food never enters into the liver or gall
bladder.
Tuesday, May 17, 2011
Pancreas
The pancreas is a triangular
organ that lies between the
stomach and the first part of
the small intestine.
The pancreas produces
enzymes which flow into the
small intestine and help break
down starches, proteins and
fats.
Food never enters the
pancreas.
Tuesday, May 17, 2011
Large Intestine (Colon)
The large intestine is the last section of the
digestive system. It is about 1 and a half
meters long.
It contains bacteria which feed on the
material passing through which helps to
produce vitamins.
As material moves through the large
intestine water is absorbed into the
bloodstream.
The remaining material is moved to the
rectum where waste is compressed into
solid form. It is then expelled from the body
through the anus.
Tuesday, May 17, 2011