Topic: Digestive System
Aim: Describe the parts and functions of
the digestive system.
Do Now: Take out the Chemistry homework
sheet.
HW: Ditto – Midterm Review: Cells (both
sides)
Food Label Activity due Tuesday!
Did you know....
• 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!!
• What you ate for breakfast, that was
not digested will come out in about 48
hours-normally.
• From intake to outlet, the digestive
tract is about thirty feet long.
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)
http://kidshealth.org/misc/movie/bodybasics/digestive_system.html
These glands may become swollen and
painful if you develop certain conditions,
such as mumps
• Chemical digestion (STARCH)
– Salivary glands secrete saliva
Did you know....
• We make 1 to 3 pints of saliva a day
• 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…
2. Epiglottis • Small flap of
tissue
• Covers windpipe
when you swallow
• Prevents choking
3. Esophagus
esophagus
• Tube that
pushes food
down into
stomach by
PERISTALSIS
• NO
DIGESTION
Did you know....
• An adult esophagus ranges
from 10 to 14 inches in
length, and 1 inch in
diameter
Opening to stomach from
the esophagus
4.Stomach
• Chemical digestion of proteins
• Mucus lining (protection)
http://www.youtube.com/watch?v=gfDrdilQsGY&feature=related
Did you know....
• An adult’s stomach can hold
approximately 1.5 liters of material.
• Food sloshing in the stomach can
last 3-4 hours.
• The stomach's wall is lined with
three layers of powerful muscles.
Topic: Digestive System
Aim: Describe the parts and functions of
the digestive system.
Do Now: Take out the Chemistry homework
sheet and cell homework sheet.
HW: Ditto – Cell Transport and Respiration
Food Label Activity due Tuesday!
5.Small intestine
http://kidshealt
h.org/misc/mo
vie/bodybasic
s/digestive_sy
stem.html
Length = 4-7 meters
Duodenum  first part of
the SI
• Where MOST chemical digestion
occurs
• Digestion ENDS here
• Lined with VILLI: folds that
absorb nutrients into the blood
6.Large intestine
http://www.youtube.com/watch?v=9fN6sm5hu48
http://www.youtube.com/watch?v=1o8TpVcrTdg&feature=fvwp
&NR=1
The function of the
appendix is unknown.
One theory is that the
appendix acts as a
storehouse for good
bacteria, “rebooting” the
digestive system after
diarrheal illnesses. Other
experts believe the
appendix is just a
useless remnant from
our evolutionary past.
Surgical removal of the
appendix causes no
observable health
problems.
• NO DIGESTION
• Absorption of water
• Forms feces (undigested
food)
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?
• Did you know....
• Within the colon, a typical
person harbors more than 400
distinct species of bacteria.
7.Rectum
• Last part of
large
intestine
• Stores feces
8.Anus
• Where feces is
egested out of
the body