The Digestive System Notes
Digestive System
• Purpose: to break down the food we eat into
nutrients so the body can use the nutrients to
build and nourish cells and provide energy
• digestion: the process of breaking down food
into a form the body can use
• Nutrients: substances in food the body needs
to work properly
Digestive System
• Digestion begins in your mouth.
• Before you begin eating when you see, smell or think
about food saliva begins to form in your mouth.
• Salivary glands under the tongue and in your cheeks
produce saliva to moisten food as it is chewed. Salivary
glands also secrete enzymes which break down starches
in the mouth.
Esophagus(Oesophagus)
• Muscular tube(10 inches long) that moves food
to your stomach through muscular contractions
called peristalsis. When you swallow a special
flap called the epiglottis closes so food does not
go down your windpipe.
Stomach
Your stomach mixes, breaks down, and churns
food with its strong muscular walls. Gastric juice
from the stomach walls helps break down the
food and helps kill bacteria from the food.
Small Intestine
The small intestine is located beneath
your stomach. An adult’s small
intestine is 22 feet long stretched out.
Your food may spend as long as 4
hours in the small intestine. The small
intestines breaks down the food
mixture even more so your body can
absorb all the nutrients-vitamins,
minerals, carbohydrates, proteins,
and fats. The villi in your small
intestine absorb the nutrients and
carry them to the bloodstream
Liver and Gall
Bladder
• The liver produces bile. The nutrient rich blood from
the small intestines goes to the liver for processing.
The liver filters out harmful substances or waste. The
liver sends nutrients to other parts of the body and
keeps some for storage
• The gall bladder stores the bile(produced by the liver).
The gall bladder sends bile to the small intestines to
help absorb fats into the blood stream
Pancreas
• The pancreas also aids digestion in the small
intestines by secreting enzymes into the small
intestine for starch and protein digestion.
Large Intestine
• The large intestine is wider than the small intestine
and not as long.(5 feet stretched out)
• Once the most of the nutrients have been absorbed
in the small intestine the left over food mixture
(which is mostly waste) goes to the large intestine.
• As this mixture passes through the large
intestine(colon) water and some minerals are
absorbed into the blood. Any solid waste left over is
pushed in the rectum until it leaves your body