The Digestive
System
Digestion involves:
• Breaking down of food into smaller
pieces(mechanical or chemical)
• The mixing of food
• Movement through the digestive
tract
How Food is digested
Digestive System
Description
• The digestive tract is a series of hollow
organs joined in a tube from the mouth to
the anus. Food passes through the
digestive tract.
• Accessory organs include the liver, gall
bladder, and pancreas. Food does not pass
through these organs.
Identify the organs of
the digestive system
Mouth
• Teeth bite off and chew food into a
soft pulp that is easy to swallow.
• Chewing mixes the food with saliva,
from salivary glands around the
mouth and face, to make it moist
and easy to swallow.
Mouth
• Enzymes in the saliva begin digestion of carbohydrates.
• Mechanical digestion - teeth
• Chemical digestion – saliva
• 11 cm long
Esophagus
• The esophagus is a muscular tube. It takes food from the throat and pushes it down through the neck, and into the stomach.
• It moves food by waves of muscle contraction called peristalsis.
• About 25 cm long
Stomach
• The stomach has thick muscles in its wall that contract to mash the food into chyme.
• Strong digestive juices in the lining of the stomach cause a chemical breakdown of food and dissolve nutrients.
• About 22 cm long
Small Intestine
• This part of the digestive tract is narrow, but very long - about 20 feet or 690 cm.
• Food is broken down into small enough pieces so nutrients can be absorbed into the blood(diffusion) and taken to vital organs.
• Enzymes continue the chemical reactions on the food.
Large Intestine
• Absorbs extra nutrients
and water
• Forms wastes into solid
feces
• About 125cm long
Gastrodigestivestsytem.com
Rectum and Anus
• The end of the large
intestine and the next
part of the tract; the
rectum stores the feces.
• Feces are finally
squeezed through a ring
of muscle, the anus,
and out of the body.
Gastrodigestivestsytem.com
Pancreas
• Makes digestive juices
called enzymes which
help to digest food
further as it enters the
small intestines.
Aboutkidshealth.ca
Gall Bladder
• A small baglike part
under the liver.
• Stores a fluid called
bile, which is made in
the liver.
• It helps to digest fatty
foods and also contains
wastes for removal. Aboutkidshealth.ca
Liver
• The liver is like a food-processing factory
• Blood from the intestines enters to the liver bringing nutrients
• It stores some of what it receives.
• Changes it into another form or releases the nutrients back into the blood
Aboutkidshealth.ca
For more information
about the digestive
system, click here
http://kidshealth.org/kid/body/digest_noSW.html