Transcript digestion - lovettlifescience

The Digestive System
2012
What happens to food after
it enters your mouth?
 1. ingestion- act of eating, or putting food into your
mouth
 2. digestion-mechanical and chemical breakdown of
food into small particles & molecules that your
body can absorb and use.
 3.absorption-cells take in small molecules of
digested food
 4. elimination-undigested food & wastes are
eliminated
Types of digestion
 Mechanical- food is physically broken down (chew,
grind, or mash food)
 Chemical – breakdown food into small molecules
with enzymes (proteins)
The Food Journey
 Mouth
 Esophagus
 Stomach
 Small intestine
 Large intestine
Mouth
 Mechanical digestion begins in your mouth with
chewing.
 Your salivary glands produce saliva (about 1 liter a
day!) They contain enzymes that help breakdown
food.
Esophagus
 Muscular tube that connects the mouth to the
stomach.
 Food moves through the esophagus by muscle
contractions called peristalsis
 It is like the squeezing of a tube of toothpaste
 ewwwwwwwwww!
Stomach
 Large hollow organ
 It stores food
 Aids in chemical digestion
 Contains acidic fluid called gastric juice, this acid
helps breakdown your food further
 Another chemical in your stomach is pepsin – an
enzyme that breaks down proteins into amino acids
Small intestine
 Long tube connected to the stomach
 Site of chemical digestion and nutrients absorption
 Inside of small intestine is lined with fingerlike
projections called villi (plural) villus (singular)
 Each villus contains small blood vessels through
which nutrients diffuse into blood stream
Large intestine
 Water is absorbed here
 Materials that pass through the large intestine are
waste products
 Same motion as in your esophagus (peristalsis)
forces the semi-solid waste into the last section of
large intestine
 Rectum and anus- muscles here control the release
of this waste called feces