Download 2 Types of Digestion

TOPIC: Nutrition
AIM: What are the
parts and functions of
the digestive system?
2 Types
of
Digestion
1.Mechanical
•Large
Digestion
pieces
of food are
physically
broken down
into smaller
pieces
•Increases surface
area of food to speed
up chemical digestion
• Makes food easier to
swallow
• Example: Teeth
2.Chemical • Complex
Digestion molecules are
broken down
into smaller
molecules
•HOW?
•By using digestive
enzymes
• Carbs (starches) 
simple sugars (glucose)
• Proteins  amino acids
Digestive •One
System
way tube
You are a tube inside a
tube…
The tube starts
here:
And although
there are a few
twists and turns
along the way…
It comes out here:
Anything that goes
into the mouth does
not become part of
the body until it is
absorbed (taken in)
in a part called the
small intestine.
Function • Breakdown of food
into pieces small
enough for
nutrients to diffuse
into cells
Path
of
Food
1. Mouth (oral cavity)
TEETH
Incisors
Canine
Premolars
Molars
Tongue
Salivary
glands
Opening of a
salivary gland duct
“Wisdom”
tooth
•Mechanical digestion
(teeth)
• Saliva – produced by
salivary glands
a. moistens food
b. Chemical digestion
• Enzyme that digests
starch  sugar
Epiglottis • Small flap of
tissue
• Closes over
windpipe when
you swallow
• To prevent
choking
2. Esophagus
esophagus
• Connects mouth to
stomach
• NO DIGESTION
• Peristalsis: muscular
movement that pushes
food along
3. Stomach
- Where protein digestion begins
• Where gastric juice
is made.
• Gastric Juice contains:
1.Hydrochloric acid 
makes stomach acidic
2. Enzymes that
chemically breaks down
PROTEINS
b. Mucus = protects
stomach wall
c. Mechanical digestion =
food churned and
mixed  chyme
(mixture of partially
digested food)
4. Small intestine
• Length = 4-7 meters
• Where most chemical
digestion occurs
• ALL digestion ends after the
first part of the small
intestine called the
Duodenum. In the 2nd part
Of the SI, Absorption of
Nutrients Occurs.
• Intestinal juice =
• Contains enzymes that
digest food
Accessory
•Food
organs
DOES
NOT pass
through
these organs
•Help the SI
Liver
Stomach
Gall
bladder
Duodenum
Pancreas
Liver
• Produces bile
• Bile travels to SI
• Emulsification of
fats  breaks down fat
into smaller droplets
Big fat
droplet
Gall Bladder
• Stores bile
Pancreas
• Makes pancreatic juice 
into SI
• Contains enzymes to
chemically digest food
Villi
• Rest of small intestine
lined with VILLI
(tiny folds)
Villi
Outer wall
Inner wall
Pathway
for Food
• Where nutrients diffuse
(are absorbed) into blood
nutrients
•Increase surface
area for nutrient
absorption
5. Large intestine
•NO DIGESTION
•Reabsorbs water
•Forms feces
(undigested food)
•Contains bacteria
(make vitamins)
If you squeezed out all of the bacteria
that lives in your intestines, you could
almost fill up a coffee mug. Anyone want
a sip?
6.
Rectum
•Last part
of LI
•Stores
feces
7. Anus•Where
feces is
egested
Did you know…
-Your teeth started growing 3 months before you were even born.
-The hardest substance in your body is the enamel on your teeth.
-As you are sitting there listening, more than 100 million germs are
swimming, feeding, reproducing, and making waste in the area behind your
lips. In your mouth there are more living things than there are people in
Australia and Canada combined…
• REVIEW
• 1. Where does mechanical digestion
begin? How?
• 2. Where does chemical digestion
begin? How?
• 3. Where does chemical digestion end?
• 4. Where does most chemical digestion
occur?
• 5. What is the function of the liver?
• 6. What are nutrients absorbed once
food has been completely broken down.
• Did you know....
• An adult esophagus (also called gullet)
ranges from 10 to 14 inches in length,
and 1 inch in diameter
• We make 1 to 3 pints of saliva a day
• An adults stomach can hold
approximately 1.5 liters of material
• Food sloshing in the stomach can last 34 hours
• The stomach's wall is lined with three
layers of powerful muscles
• Did you know....
• The Average human being consumes
about 500kg of food per year.
• Within the colon, a typical person
harbors more than 400 distinct
species of bacteria
• On average, the stomach produces
2 liters of Hydrochloric Acid (HCl)
daily
• Did you know....
• A full grown horse’s coiled up intestines
are 89 feet long
• Food stays in your stomach for 2 to 3
hours
• Americans eat about 700 million pounds
of peanut butter.
• Americans eat over 2 billion pounds of
chocolate a year.
• In your lifetime, your digestive system
may handle about 50 tons!!
• Did you know....
• What you ate for breakfast,
that was not digested will
come out in about 48 hoursnormally.
• From intake to outlet, the
digestive tract is about thirty
feet long