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Project 3.2.2 and Project 3.2.3: Student Resource
Sheet
Use the information found below to guide your research and to design your model. Take
notes, answer questions, and complete sketches in your laboratory journal.
1. Oral cavity, pharynx, (must also include accessory organs such as salivary
glands, tongue, and teeth)
 What is the oral cavity and what does it contain?
o The oral cavity is the first section of the digestive system that contains the
lips, tongue, teeth, and roof of the mouth
 What is the function of the salivary glands?
o To produce saliva, a liquid that contains amylase to break down starch.
 What is the function of the tongue?
o To assist with chewing and swallowing food, as well as speech.
 What is a bolus?
o A small glob of food that is about to be swallowed.
 Where are the soft and hard palate located and what are their functions?
o The soft palate is the gums in the mouth, and the hard palate is the bone.
 What mechanical and chemical digestion occurs in the oral cavity?
o Chewing grinds up food and amylase breaks down starches chemically.
 What mechanisms are in place to make sure food does not “go down the wrong
tube” and into the windpipe?
o The epiglottis, a flap of tissue, keeps food from going into the trachea.
2. Esophagus and Stomach
 What is peristaltic movement and how does it function in the esophagus?
o It is a series of wave-like movements of muscles that moves food down
the esophagus.
 Does any digestion of food occur in the esophagus?
o No, although it is compressed.
 What are the primary functions of the stomach?
o To masticate the food and secrete acids to chemically enhance digestion.
 What is chyme and how does the stomach mix this material?
o It is partially digested food which is mixed in the stomach via contractions.
 What role does the stomach play in decontaminating the incoming food matter?
o The acid produced by the stomach decontaminates the food.
 What cells in the stomach function to form enzymes and acids?
o Parietal cells (Gastric acid) and Chief cells (Pepsin).
 Why doesn’t gastric juice digest the inside of the stomach?
o The stomach is protected by a lining that is recreated very frequently, and
the enzymes that are released are in an inactivated form.
 What are sphincters and how are they related to the stomach?
© 2014 Project Lead The Way, Inc.
Human Body Systems Project 3.2.2 and Project 3.2.3 Student Resource Sheet – Page 1
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o They are openings of the stomach that keep the contents of the stomach
contained.
What mechanical and chemical digestion occurs in the stomach?
o The food is crushed even further and some proteins and fats are broken
down.
3. Small Intestine and Large Intestine
 What are the three sections of the small intestine and what role does each
section play in digestion or absorption?
o Duodenum- Food enters the small intestine and this is where most
chemical digestion occurs.
o Jejunum- Small nutrient particles are absorbed.
o Ilium- Absorbs Vitamin B12 and bile salts.
 What is the pH within the small intestine and how is this pH maintained?
o The pH is approximately 6.0, and is maintained by buffers.
 Where do bile and pancreatic enzymes enter the small intestine?
o The cystic duct, which connects the liver to the intestines.
 How does food move through the intestines?
o The organ walls move (peristalsis) and moves the food onward.
 What enzymes act inside the small intestine and what are the functions of these
enzymes?
o Amylase- Breaks down carbohydrates.
o Protease- Breaks down proteins into amino acids.
o Lipase- Breaks down fats.
o Nuclease- Breaks down nucleic acids.
 What is the function of the large intestine in relation to digestion?
o Water is absorbed and waste products are stored.
 What are the three sections of the large intestine and what roles does each play
in digestion or absorption?
o Ascending- Extraction of water begins.
o Transverse- Extracts all remaining water and nutrients.
o Descending- Stores remaining food waste that will be emptied to rectum.
 How does the large intestine help maintain a water balance in the body?
o The large intestine reabsorbs water from the waste products.
4. Pancreas, Liver and Gallbladder
 What are the size and the location of the pancreas?
o It is approximately 6 inches long and sits behind the stomach.
 What are the different functions of the pancreas, and how is the pancreas directly
related to digestion?
o Pancreas releases enzymes and hormones, and in digestion, enzymes
released by it break food down.
 How does the pancreas connect to the rest of the digestive system?
o The pancreas attaches to the small intestine at the pancreatic duct.
 What enzymes are produced by the pancreas and what are their functions?
o Lipase- breaks down lipids
© 2014 Project Lead The Way, Inc.
Human Body Systems Project 3.2.2 and Project 3.2.3 Student Resource Sheet – Page 2
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o Amylase- breaks down carbohydrates
o Tryptase- breaks down proteins
o Nuclease- breaks down nucleic acids
How is insulin related to the digestive system?
o Insulin is released in amounts appropriate to the amount of glucose
entering the body.
What is the size of the liver and where is it located?
o It is a large, approximately 3 pound, organ that sits on the right side of the
stomach.
How does the liver function in relation to digestion?
o The liver detoxifies the blood coming from the digestive tract so that the
essential nutrients can be passed on to the rest of the body.
What are other functions of the liver in the body?
o The liver metabolizes drugs, detoxifies chemicals, and secretes bile.
What is the relationship between the liver and the gallbladder?
o The gallbladder stores the bile that the liver creates.
What is the function of bile and where does it enter the digestive tract?
o Bile helps to digest lipids and enters the GI tract at the bile duct
Each group will be assigned one of the following bites of food. First, think about the
class of molecule this food item represents and then identify the specific enzymes that
would break this polymer into monomers. Remember to describe features that help
mechanically digest this bite. Depending on your food item, you may need to do some
additional research.
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Bread
Butter
Steak
Celery
Skittles
© 2014 Project Lead The Way, Inc.
Human Body Systems Project 3.2.2 and Project 3.2.3 Student Resource Sheet – Page 3