Digestive System Notes
Mouth
Esophagus
Stomach
Small Intestine
Large
Intestine
System have BFS…. IC
Interconnectedness
Changes
The “BFS”
• Behavior = Role (role of each part)
• Function = Purpose (purpose of the whole
system)
• Structure = Parts
BF  Behavior vs. Function
Behavior is specific
Function is general
System have BFS…. IC
• Interconnection – there are links between
parts
• Changes – If a part fails to perform, it will
affect the whole system
How do the
COMPONENTS of a
System
INTERCONNECT?
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
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?
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
ABSORBED
ELIMINATED
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 , bile, HCL acid
• 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 digestion
Digestion
Definition
• Digestion is the breaking down of food into
smaller and simpler substances
• Mechanical digestion and Chemical digestion
do this in different ways
ABSORBED
ELIMINATED
Chemical Digestion is the
breaking down of large
complicated molecules
into simpler ones by the
use of enzymes
http://web.ukonline.co.uk/webwise/spinneret/other/anenz.htm
Orange- food
Red and yellowproducts
ENZYME
(glucose)
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
Mouth / Teeth
Esophagus
Liver
Stomach
Small intestine
Large intestine
Rectum
Anus
Appendix
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
Epiglottis
Image source:
http://www.umm.edu/imagepages/19595.htm
Animation
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.whfoods.com/genpage.php?tname=faq&dbid=16#digestion
Animation of Digestion
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