Digestion
Get that out of your mouth; you
don’t know where that has been.
How this works.
• What is happening inside as we eat this cookie?
• Look for words in bold because there definitions
are in the test.
• Words in italic will be in the multiple choice.
• Underlined words will be in a labeling diagram.
We will mark on the overhead.
• If a word is in bold, italicized, and underlined will
be a health concern.
A tube within a tube.
• Gastrointestinal Tract =
Alimentary Canal.
• Purpose –
– Digestion.
• Cookie will make 9 stops on its
way towards Defecation.
• Whole point of this process is
for Intake: constant supply of
energy and building blocks
provided by food.
• Can you identify the organs at
the left?
Mouth = Oral Cavity
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This is where the tube starts.
Teeth are used as tiny hammers to break
down food.
– Can you identify the teeth on the
overhead?
Mastication?
Tongue is important for tasting, chewing,
and swallowing.
– Where are you tasting this cookie?
Salivary Glands send saliva to moisten food
and help break it down further.
Enzymes in saliva help breakdown food.
Now swallow (Deglutition) the cookie.
As it is swallowed, it is only suppose to
down 1 passage way: esophagus. 2
“appendages” help keep the cookie on its
way: Uvula, which is that ‘hangy down
thingy” at the back of your throat and the
Epiglottis.
Halitosis is bad breath.
Esophagus
• Esophagus is the slide that
the bolus takes from the mouth
to the stomach.
• Before the bolus enters the
stomach it must open a “door”:
Cardiac Sphincter.
• This is all that the esophagus
does; nothing is released into
the cookie and nothing is taken
out.
• Just a passage way.
Stomach
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Bolus enters the Stomach, where it
completely changes.
Gastric juices and liquid from the meal mix
in with the solid mass of the cookie to make
Chyme.
What are the folds in the stomach that
increase surface area inside the
stomach?
Stomach is where the main breakdown
occurs and mixes everything that is inside
together.
When the chyme is mixed, it must open
another “door”: Pyloric Sphincter, which
prevents food from entering the small
intestine too soon.
Hiatal Hernia - Protrusion of the stomach
through opening in the diaphragm
Gastrointestinal Ulcer - sores on the
mucous membrane of any part of the GI
tract
Small Intestine
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Made up of 3 sections: Duodenum,
Jejunum, and Ileum.
Duodenum is first part of the SI. It
receives the bile from the liver (slide
coming). Is about 10 in. long.
Jejunum is second part of SI. It is 8 ft.
long.
Ileum is the last part of SI. Connects to
the large intestine (next slide).
Enzymes also enter SI to continue the
breakdown of protein, sugars, and
fats.
This is where Absorption (passage of
material through walls to blood) takes
place.
Peristalsis is used to help move the
food along the SI.
Large Intestine
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Has 4 parts: Cecum, Colon, sigmoid colon,
and Rectum.
Cecum is the first part of LI. It turns waste in
feces.
Colon is the second part of LI. Horseshoe
shaped and makes up the majority of the LI.
Sigmoid colon is the third part and is
basically an extension to the last part of the
LI.
Rectum is the last part of the LI. Attaches to
the Anus, which is a fancy word for butt.
Waste hangs out here for 12 to 24 hrs.
It is about 5 ft. long, which is as long as me.
The cookie will then exit the system and will
not even have any resemblance to that
cookie. Here is where the tube ends.
Ulcerative Colitis - recurring ulcers and
inflammation of the large intestine, Stress
Appendicitis - Inflammation of the appendix
Liver (accessory organ)
• Food never passes
through the liver, but it
plays a role in digestion.
• It is the largest gland and
weighs about 3 lbs.
• Gives Bile into the
gallbladder (next slide).
• Jaundice is a sign of liver
trouble.
• Cirrhosis is from chronic
liver trouble.
Gallbladder (Accessory organ)
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Has been storing bile from the liver;
waiting to be used.
When needed, the gallbladder
releases the bile into the duodenum.
Cholecystitis - Inflammation of the
gallbladder
Gallstones:
– Hard, pebble-like deposits that
form inside the gallbladder
– May be as small as a grain of
sand or as large as a golf ball.
– Can be made from cholesterol or
too much bile.
– Are more common in women,
Native Americans and other ethnic
groups, and people over 40.
– They run in families.
Pancreas (Accessory Organ)
• Helps secret enzymes into the
SI.
• Has exocrine and endocrine
functions.
• Exocrine glands differ from
endocrine glands, because
they have ducts that deliver the
products in the superficial part
of the body, such as the skin,
or in the inner part where they
are necessary, such as the
pancreatic juice that is carried
into the intestine to aid
digestion.