Download 1. Digestive System Intro and Anatomy

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The Human Digestive System
We’ll begin with three mysteries…
Mystery #1 - The Amazing Weight Loss
You may have seen this news story during your vacation:
http://www.nbcnews.com/health/rooting-her-strangers-donate-50k-texas-girls-life-saving-obesity-2D11819010
(text version) : http://www.nbcnews.com/health/obese-starving-girl-12-denied-weight-loss-surgery-rare-illness-2D11803240
How can gastric bypass surgery help people with obesity? How does the surgery work and why
do people lose weight?
Some obesity background: Overeating sugar and starch are certainly major causes of obesity, but
there are other reasons as well. For example, there’s a hormone called leptin made in our fat
cells that’s supposed to be released when we’ve eaten. Leptin then travels to our hypothalamus,
where it latches on to some receptors and makes us stop eating. Leptin says, “You’re full!”
(By the way, leptin has a chemical opposite, called ghrelin. Ghrelin is produced in your stomach
and other parts of your digestive system; its job is to say, “_______________________”)
But some people have damaged leptin systems, and their brains never get the signal to stop
eating. This is one (but not the only) cause of obesity.
Mystery # 2 - Beans! Beans!
“Beans! Beans! The musical fruit! The more you eat the
more you...”
Or is it… “Beans! Beans! Good for your heart! The
more you eat the more you...”
However you may have heard this playground rhyme,
it’s true. But why do beans give you gas?
And why does the product “BEANO” prevent gas?
www.beanogas.com
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Mystery # 3 - H.C.O.D.
From the US Department of Commerce:
From the Centers for Disease Control:
Also from CDC:
and…
http://www.cdc.gov/obesity/data/animated_map_slides/map24.jpg
What’s the relationship between sugar consumption, obesity and Type 2 diabetes?
Why does this relationship exist?
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Before we begin to learn the anatomy of the
digestive system, take a look at this diagram.
How are humans like the bristle worms some people
observed from the pond samples at the start of the
year? (Let’s take a look at some video.)
What is the point of the digestive system?
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We’ll start by learning the basic anatomy of the human digestive system.
Your first task in learning about the digestive system is to use various resources to learn the
digestive system anatomy, take a quiz and answer the weight-loss surgery mystery.
The quiz will ask you to do two things:
1. Create an illustration, in class from scratch, which correctly places the following items in the
digestive system: (The illustration does NOT have to be literal - we’ll look at an example of a figurative
illustration.)
Anus
Liver
Appendix
Mouth
Ascending Colon
Pancreas
Descending Colon
Rectum
Duodenum (part of small intestine)
Salivary glands
Esophagus
Stomach
Gallbladder
Teeth
Gastroesophageal Sphincter
(or Lower Esophageal Sphincter)
Tongue
Ileum (part of small intestine)
Transverse Colon
Jejunum (part of small intestine)
Sigmoid Colon
2. Match the 20 items above to a definition of their function
You have a number of resources to learn these 20 parts and their functions.
1. A Quiz for Fun - how much do you already know?
2. A Quick Tour with some hands-on stops along the way
3. There are ten links you can explore on the Food, Nutrition and Digestive System page of the
course website. Look for “Digestive System Information - Learning the Anatomy”
4. You may examine the teaching torso in the classroom.
5. You may use “Visible Body” at the computer on my desk.
6. You may look at the models and charts in the room.
7. You may print any digestive system diagrams you find useful.
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Resource 1: A Quiz for Fun - how much do you already know?
A Brief Tour of the Digestive System
1. A fancy term for the route food travels in your body is
a. The Cardiovascular Circuit
b. The Alimentary Canal
c. The Lymphatic Pathway
2. The chemicals in our bodies which digest food are collectively known as
a. Enzymes
b. Antibodies
c. Hormones
3. The length of the food pathway is approximately
a. 12 feet
b. 27 feet
c. 64 feet
4. The first digestive chemical in your digestive system is
a. Mucus
b. Stomach Acid
c. Saliva
5. When food is swallowed it moves in order through the
a. Pharynx, esophagus, stomach
b. Esophagus, stomach, pharynx
c. Stomach, esophagus, pharynx
6. Another word for stomach enzymes is
a. Colon fluid
b. Mucus jelly
c. Gastric juices
7. As soon as chyme moves into the small intestine, it is bathed in enzymes secreted from the
a. Pancreas and liver
b. Liver and spleen
c. Spleen and kidneys
8. The small intestine, if stretched out, is how long?
a. 5 to 6 feet
b. 9 to 10 feet
c. 14 to 15 feet
9. True or False: The small intestine is the most important absorbing organ of the digestive
system, and carbs, fat and protein are all at least partially digested there.
10. The large intestine is also known as the
a. Spleen
b. Omentum
c. Colon
From the video: What is the purpose of the large intestine?
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Resource 2: A Quick Tour with some hands-on stops along the way.
Stop Number 1: The salivary glands
Saliva moistens food and also contains an enzyme which begins digesting amylose starch. We’ll
experiment more with that enzyme, called _________________________, later.
http://www.youtube.com/watch?v=BV4Ze
NvXfhk&sns=em
Do not try this near friends, family or
anyone you wish to impress socially.
The hole you see below your tongue is
called your sublingual caruncle.
We tend to consume a lot of starch, and yet we only keep food in our mouths for a few seconds
before swallowing. That’s not enough time for the amylase to get much digesting done.
Therefore, how might our bodies solve the problem of getting the starch we eat to have more
contact time with amylase?
Stop Number 2: The Gastroesophageal Sphincter (also called the Lower Esophageal Sphincter):
http://www.youtube.com/watch?v=PwVAnwpbC_I
You can hear and feel the opening of your GES (or LES)
1. Disinfect and put on the stethoscope
2. Place the drum on your lowest layer of clothing at a spot that is
two inches below and two inches to the left of the end of your sternum
(breastbone)
3. Be quiet
4. Swallow a big swallow of water
5. Listen closely
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Stop Number 3: The Stomach
The stomach begins the digestion of protein. Gastric juice contains the enzyme pepsin, as well
as hydrochloric acid. But how could you determine which one is more crucial in the digestion
of protein?
Purpose: The purpose of this experiment is to determine whether pepsin or hydrochloric acid is
more important in digesting protein.
Hypothesis:
Materials:
Test tubes
Pepsin
Hydrochloric acid (HCl)
A protein substrate; we will use __________________________
Procedure:
Results:
Conclusion:
To learn more about the stomach, we will read Chapter 10 of Mary Roach’s Gulp: Adventures on the
Alimentary Canal (Norton, 2013). (If you want to read a lot of weird stories about digestion, read the
whole book!)
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Stop Number 4: The Duodenum, the beginning of the small intestine
www.faculty.ucc.edu
A lot of action takes place when food leaves the
stomach and passes into the duodenum, the first part of
the small intestine. From the diagram below, can you
determine how the liver, gallbladder and pancreas help
in digestion?
The liver produces bile and stores it in the gallbladder.
Bile is chemically similar to dish detergent; both
chemicals emulsify fat. We’ll experiment with some
unsaturated fat: corn oil.
2.
3.
4.
5.
6.
1. Prepare two test tubes by adding some corn oil
and some water to each. The tubes should be about half full, and they should have enough
oil and water so you can see two clear layers.
Swirl the test tubes and notice the size of the oil droplets you see as well as the time it
takes for the oil layer to separate from the water.
Add a drop of dishwashing detergent to ONE test tube and swirl it.
How does the detergent affect the oil in the second tube when it is swirled?
Bile and detergent are both emulsifiers. From your observations, what does an emulsifier
do?
Why is emulsification of fat so crucial for us?
Bile emulsifies fats droplets into individual particles called triglycerides, which will be further
digested later.
Stop Number 5: Where are we?
Look at the sausage casings. What are they?
Why must they be so long?
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Stop Number….What Stop is This? Where are we? I’m Lost!
Take a look at the pictures. They were taken with an endoscope.
Where do you think each was taken?
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One last stop.
Where are we?
What is this?
www.openstudy.com
Where might you find these structures?
Why are these structures so important?
Remaining Resources to explore before the quiz:
1. There are ten links you can explore on the Food, Nutrition and Digestive System page of the
course website. Look for “Digestive System Information - Learning the Anatomy”
2. You may examine the teaching torso in the classroom.
3. You may use “Visible Body” at the computer on my desk.
4. You may look at the models and charts in the room.
5. You may print any digestive system diagrams you find useful.
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Solving Mystery #1 - The Amazing Weight Loss.
After taking the quiz, figure out how surgery takes place to dramatically reduce weight in obese
individuals (include the bariatric surgery lesson from last year here). How is the digestive system
altered, and why does that alteration work?