The Human Digestive System We’ll begin with three mysteries… Mystery #1 The Amazing Weight Loss



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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
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?

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?

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.




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?


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=BV4ZeNvXfhk&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)

  1. Be quiet

  2. Swallow a big swallow of water

  3. Listen closely

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!)


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.





  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.

  2. 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.

  3. Add a drop of dishwashing detergent to ONE test tube and swirl it.

  4. How does the detergent affect the oil in the second tube when it is swirled?

  5. Bile and detergent are both emulsifiers. From your observations, what does an emulsifier do?

  6. 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?

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?










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.

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?


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