Presented By: Sam Lund, Donovan Parker,
Tom Srebernak
1. Extract nutrients from food
2. Transform nutrients into useful forms
Ex. Oreo= Glucose (sugar)
3. Absorb nutrients and distribute them where
they are needed
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Ingestion: Intake of nutrients
Digestion: Breakdown of large particles into
smaller ones
Absorption: Uptake of nutrient molecules
Defecation: Elimination of undigested
residues
1. Intake
-
Breaks up food
Moves food through the GI tract (Peristalsis)
Mixes with digestive enzymes
2. Secretion
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Release of enzymes and hormones for chemical
digestion and regulation
3. Membrane Transport
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Absorption of nutrients from the tissues by the
blood and lymph for transport
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Mechanical: Physical breakdown of food
Chemical: Digestive enzymes hydrolyze food
particles to break larger molecules into smaller
ones
Some nutrients are absorbed without digestion
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Vitamins, minerals, cholesterol, water
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Oral Cavity
Pharynx
Esophagus
Stomach
Small Intestine
Large Intestine
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6 meters in length
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Functions:
Chemical Digestion
 Nutrient Absorption
 Nutrient Transportation
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Digestion and
absorption of food
Digestive enzymes
secreted by the
pancreas
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Enter the small
intestine via the
pancreatic duct.
Duodenum (25 cm)
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Food mixes with bile
from the gallbladder.
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Jejunum (2.5m)
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Absorbs nutrients into
the bloodstream.
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Ileum (3.6 m)
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Reabsorbs bile acids.
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1.5 meters long
Responsible for absorption of water from the
indigestible residue of food
Ascending Colon:
Up the right side
Descending Colon:
Down the left side
Cecum: Sac on
lower right side
Sigmoid Colon:
S-shaped
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Ascending Colon-Removes water and
other nutrients
Transverse Colon-Expulsion of waste
materials, continues leaching out
Descending Colon-Absorbs water from
fecal matter. Stores food particles that
are to be emptied into the rectum.
Sigmoid Colon- Make and eliminate
feces. Contains 60 varieties of bacteria
Rectum- Temporary storage for fecal
matter before it’s eliminated from the
body through the anal canal.
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Functions:
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A. Ingestion: Cheeks
lips and tongue mobilize
food
B. Digestion:
 Mechanical
 Mastication
 Chemical
 3 salivary glands
 Digests some
starches and fat
Purpose: Pharyngeal
constrictors force food
down during
swallowing
Divided into 3 parts:
 Epipharynx
 Mesopharynx
 Hypopharynx
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Straight Muscular
tube about 1 foot long
Purpose: Muscular
contraction moves
food towards stomach
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Muscular sac on the left
side of the peritoneal
cavity
Functions:
Food storage
 Mechanical
digestion
 Chemical digestion
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Saliva:
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Amylase: Breaks down starch
Lipase: Breaks down fats when it enters the stomach
Stomach:
HCL: Activates enzymes, breaks up foods
Pepsin: Digests proteins
Renin: Digests milk
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Starches  bloodstream
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Fats  lymph vessels (lacteals)
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Proteins  bloodstream