How do the
COMPONENTS of a
System
INTERCONNECT?
http://www.whfoods.com/genpage.php?tname=faq&dbid=16#digestion
Animation of Digestion
Overview of Digestion:
New: http://www.youtube.com/watch?v=b20VRR9C37Q&feature=fvwrel
http://www.youtube.com/watc
h?v=uIRHfdrixmA&playnext=1
&videos=qKCrsqijhhs&feature=
rec-LGOUT-exp_fresh%2Bdiv1r-1-HM
INGESTION
FUNCTION/
PURPOSE OF
SYSTEM
Digestion
breakdown of food  into
molecular components
small enough to cross the
plasma membrane
Digestion
• Definition
• Digestion is the breaking down of food into
smaller and simpler substances
• Mechanical digestion and Chemical digestion
do this in different ways
Physical breakdown
Use of enzymes
(chemical
substances)
Digestion
Definition
• MECHANICAL (physical) digestion
– breaking down of food into smaller pieces
– involves: chewing, grinding, churning
• CHEMICAL digestion
– Breaking down of food into simpler substances
(building blocks)
– involves: enzymes
• ABSORPTION
– Broken down food gets from digestive tract into
the body (blood)
Mechanical Digestion
saliva
Same volume of food
saliva
saliva
Small total surface area
Larger total surface area
A larger surface area speeds up digestion
Smaller pieces allow for more areas of contact for
enzymes and digestive juices to act on speeding up
chemical digestion
CHEMICAL
MECHANICAL
Absorption
passage of
molecules
into body's
interior &
passage
throughout
the body
ELIMINATION
OF WASTE
LARGE
INTESTINES
REABSORBS
WATER & SALTS
STRUCTURE OF
SYSTEM
The Digestive System
Use the words below to label the parts of the digestive system.
Liver
large intestine
appendix
anus
oesophagus
rectumto label
small intestine
stomach
Use the words below
the parts of the
digestive mouth
system.
Liver
rectum
large intestine
small intestine
appendix
stomach
anus
mouth
oesophagus
The
Digestive
System
Mouth / Teeth
Esophagus
Liver
Stomach
Small intestine
Large intestine
Rectum
Anus
Appendix
Epiglottis
Image source:
http://www.umm.edu/imagepages/19595.htm
Animation
OBSERVING DIGESTIVE ORGANS
1. The esophagus
a. How would you describe the esophagus?
b. How is it designed to perform its behavior?
2. External and internal structure of the stomach.
a. How would you describe the external appearance of the stomach?
b. What is the action (behavior) of the stomach?
c. How is the stomach designed to perform its behavior?
3. External and internal structure of the small and large
intestines
a. Describe the appearance of the small and large intestines.
b. What are the main actions (behavior) of the small and large intestines?
c. How is the small intestine designed to perform its behavior?
Tongue Papillae
Photograph by SPL/Photo Researchers, Inc.
Cone-shaped tongue
papillae, seen here
in a colored scanning
electron micrograph,
contain nerve
endings that receive
and transmit touch
sensations to the
brain.
As we begin
chewing, the tongue
shapes food in a
ball-shaped bolus for
swallowing.
http://science.nationalgeographic.com/science/photos/digestive-system/?source=A-toZ#/tongue-papillar_1251_600x450.jpg
Inside the Human Mouth
Photograph by Lennart Nilsson
Inside the mouth, shown
magnified here, teeth,
tongue, and saliva work
together to physically and
chemically break down
food.
Humans produce up to 3
pints (1.4 liters) of saliva
daily, and chemical enzymes
in the saliva play a major
role in disintegrating starchy
foods.
http://science.nationalgeographic.com/science/photos/digestivesystem/?source=A-to-Z#/human-mouth_1002_600x450.jpg
This colored scanning
micrograph shows a cast of
blood vessels from the
external wall of the small
intestine.
Measuring about 22 feet
(6.7 meters) in length, the
small intestine performs
most of the major digestion
and absorption of nutrients.
The walls of the small
intestine are lined with
millions of projections
called villi, which absorb
and transmit nutrients into
the bloodstream.
http://science.nationalgeographic.com/science/photos/digestive-system/?source=A-toZ#/small-intestine-vessels_1211_600x450.jpg
VILLI
Image source:
http://www.sciencephoto.com/media/310014/enlarge
BEHAVIOR
http://www.youtube.com/watch?v=vFiavuyk
31s&feature=related
Wave-like
contractions
Peristalsis video clip
Image source:
http://media.photobucket.com/image/peristalsis
/hurricane78_album/peristalsis.gif?o=2
Image source:
http://www.flickr.co
m/photos/liujoanne/
2172007698/
INTERCONNECTION
Digestion
Absorption
Elimination of
Waste
Function
1) mechanical/physical & chemical digestion
2) Absorption of nutrients
3) Excretion of waste
REGION OF
FOOD TUBE
STRUCTURES
INVOLVED
BEHAVIOR/PROCESS
Contribution
to Function
Teeth
Tongue
Salivary Glands
Chewing
Moves food
Chemical digestion of starch
esophagus
muscles
peristalsis
STOMACH
Muscular sac
Stomach acid
Mixing of food with gastric juice (HCl)
producing chyme
Protein digestion
Churning of food (mechanical)
1
SMALL
INTESTINE
Duodenum
Ileum
Liver
1,2
Gall
bladder/Pancreas
Final digestion
Absorption
Produces bile (digest fats/neutralize
stomach acids)
Stores bile
Releases enzymes to help digestion
Colon
Rectum
anus
Removal of waste; reabsorb water and salts
Storing waste
excretion
2,3
MOUTH
LARGE
INTESTINE
1