Download Digestive System

DIGESTIVE SYSTEM
Pages 979-991
FUNCTION
•Breakdown of food into simpler
molecules that can be absorbed by
the body in one long tube from
mouth to anus
NUTRIENTS
•Six classes of nutrients:
1.
2.
3.
4.
carbohydrates
fats/lipids
proteins
minerals: help balance osmosis and the function of
certain cells (i.e. muscle and nerve cell)
5. vitamins: aid enzyme activity
6. water: most chemical reactions can only occur in water
(accounts for half of your body weight)
DIGESTION
•Mechanical: physical breakdown of
food
•Chewing, peristalsis (moving bolus down
the esophagus), and stomach churning
DIGESTION
•Chemical: enzymes breaking down
food into simpler forms (monomers)
•Ex: amylase and pepsin
PARTS OF THE DIGESTIVE TRACT
•Mouth
•Amylase (enzyme) is released from
glands into saliva
•Breaks down carbohydrates to
monosaccharides
DIGESTIVE TRACT
•Esophagus (connects mouth
to stomach)
•Bolus (food ball) travels
down esophagus to stomach
DIGESTIVE TRACT
•Stomach
•Muscle contractions break bolus
apart (mechanical digestion)
DIGESTIVE TRACT
Stomach continued
•Pepsin (enzyme) breaks down
proteins into amino acids
(chemical digestion)
•Released by gastric glands
•HCl keeps stomach acidic so
the pepsin can work
DIGESTIVE TRACT
•Pancreas
•Secretes sodium bicarbonate (base)
into small intestine to neutralize acid
DIGESTIVE TRACT
•Liver
•Produces bile and sends it to the
gall bladder for storage
DIGESTIVE TRACT
•Gall bladder
•Stores bile and secretes it into the small intestine
DIGESTIVE TRACT
•Small intestine
•Chemical digestion and where
most nutrients are absorbed
•Bile is secreted here to break
down fats into fatty acids
DIGESTIVE TRACT
•Small intestine continued
•Has villi: folds in lining of small
intestines
•Increases surface area for maximum
absorption
DIGESTIVE TRACT
•Large intestine/colon
•Absorption of water, minerals,
and vitamins
Salivary glands
Esophagus
Liver
Stomach
Gall bladder
Pancreas
Small intestine
Large
intestine/colon