Project 3.2.2 and Project 3.2.3: Student Resource
Sheet
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? The oral cavity is the first part
of the digestive tract and it contains the mouth along with the organs in the
mouth.
 What is the function of the salivary glands? The salivary glands produce saliva,
which keeps the mouth and other parts of the digestive system moist.
 What is the function of the tongue? The tongue aids in moving food in the
mouth, chewing, and swallowing.
 What is a bolus? A bolus is small rounded mass of a substance. Chewed food at
the moment of swallowing is an example of bolus.
 Where are the soft and hard palate located, and what are their functions? The
soft and hard palate are located at the roof of the mouth. The hard palate is at
the front, and the soft palate is at the back. The hard palate holds the root of the
teeth. The soft palate pressed down for swallowing.
 What mechanical and chemical digestion occurs in the oral cavity? The
mechanical digestion that occurs in the oral cavity is chewing. The chemical
digestion occurring in the oral cavity is the enzymes in saliva commencing the
degrading of food.
 What mechanisms are in place to make sure food does not “go down the wrong
tube” and into the windpipe? A flap of skin, known as the epiglottis, separates
the esophagus from the trachea, thus preventing food from "going down the
wrong tube".
2. Esophagus and Stomach
 What is peristaltic movement and how does it function in the esophagus?
Peristaltic movement is a type of muscle contraction and it functions in the
esophagus by helping push food to it.
 Does any digestion of food occur in the esophagus? Yes, some digestion of
food occurs in the esophagus.
 What are the primary functions of the stomach? The primary functions of the
stomach are to break down food after feeding and to extract the nutrients
necessary to the body.
 What is chyme and how does the stomach mix this material? Chyme is the
pulpy acidic fluid that passes from the stomach to the small intestine. The
stomach mixes this material by combining food, enzymes, and gastric juices.
 What role does the stomach play in decontaminating the incoming food matter?
The stomach contains a lot of acids which which help break down food matter
and kill bacteria.
 What cells in the stomach function to form enzymes and acids? Parietal cells in
the stomach function to form enzymes and acids.
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Why doesn’t gastric juice digest the inside of the stomach? The stomach is
made to be strong enough to handle the gastric juices, thus protecting itself from
being digested.
What are sphincters and how are they related to the stomach? Sphincters are
the openings into and out of the stomach. They open and close when needed to
either allow food into the stomach or to allow digested food out of the stomach.
What mechanical and chemical digestion occurs in the stomach? A type of
mechanical digestion that occurs in the stomach is churning. A type of chemical
digestion that occurs in the stomach is the role of gastric acid.
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? The three sections of the small intestine
are the duodenum, jejunum, and ileum. The duodenum receives partly-digested
food, acid, and bile. The jejunum and ileum break down food fully.
 What is the pH within the small intestine and how is this pH maintained? The pH
of within the small intestine is 6. This pH is maintained through bicarbonate ions.
 Where do bile and pancreatic enzymes enter the small intestine? Bile and
pancreatic enzymes enter the small intestine through the duodenum.
 How does food move through the intestines? The pathway of food through the
intestines is:
duodenum → jejunum → ileum → cecum → colon → rectum
 What enzymes act inside the small intestine and what are the functions of these
enzymes? The enzymes that act inside the small intestine are amylase,
protease, and lipase. Amylase acts on starch and breaks it down into small
carbohydrate molecules. Protease acts on proteins and breaks them down into
amino acids. Lipase breaks down dietary fats into smaller molecules called fatty
acids and glycerol.
 What is the function of the large intestine in relation to digestion? In relation to
digestion, the large intestine absorbs water and salts. It also stores waste
material until they're thrown out of the body.
 What are the three sections of the large intestine and what roles does each play
in digestion or absorption? The three sections of the large intestine are the
cecum, colon, and rectum. The cecum takes digested liquid from the ileum and
passes it on to the colon. The colon is the principal place for water reabsorption
and absorbs salts when needed. The rectum is where leftover waste sits until it
is ready to be emptied through the anus.
 How does the large intestine help maintain a water balance in the body? The
large intestine helps the body digest and remove water from the remains of food
(feces) after which it will go through the rectum.
4. Pancreas, Liver and Gallbladder
 What are the size and the location of the pancreas? The pancreas is about 6
inches long and sits across the back of the abdomen, behind the stomach. The
head of the pancreas is on the right side of the abdomen and is connected to
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the duodenum (the first section of the small intestine) through a small tube
called the pancreatic duct.
What are the different functions of the pancreas, and how is the pancreas
directly related to digestion? Exocrine: The pancreas contains exocrine glands
that produce enzymes important to digestion. These enzymes include trypsin
and chymotrypsin to digest proteins; amylase for the digestion of carbohydrates;
and lipase to break down fats. When food enters the stomach, these pancreatic
juices are released into a system of ducts that culminate in the main pancreatic
duct. The pancreatic duct joins the common bile duct to form the ampulla of
Vater which is located at the first portion of the small intestine, called the
duodenum. The common bile duct originates in the liver and the gallbladder and
produces another important digestive juice called bile. The pancreatic juices and
bile that are released into the duodenum, help the body to digest fats,
carbohydrates, and proteins.
Endocrine: The endocrine component of the pancreas consists of islet cells
(islets of Langerhans) that create and release important hormones directly into
the bloodstream. Two of the main pancreatic hormones are insulin, which acts to
lower blood sugar, and glucagon, which acts to raise blood sugar. Maintaining
proper blood sugar levels is crucial to the functioning of key organs including the
brain, liver, and kidneys.
How does the pancreas connect to the rest of the digestive system? It plays an
essential role in converting the food we eat into fuel for the body's cells. The
pancreas has two main functions: an exocrine function that helps in digestion
and an endocrine function that regulates blood sugar.
What enzymes are produced by the pancreas and what are their functions?
Pancreatic proteases (such as trypsin and chymotrypsin) - which help to digest
proteins.
Pancreatic amylase - which helps to digest sugars (carbohydrates).
Pancreatic lipase - which helps to digest fat.
How is insulin related to the digestive system? Insulin is released from the beta
cells in your pancreas in response to rising glucose in your bloodstream. The
pancreas detects this rise in blood glucose and starts to secrete insulin. The
pancreas detects this rise in blood glucose and starts to secrete insulin. Insulin
works by improving the uptake of glucose from the blood across cell membranes
and into the cells of the body, and so takes glucose out of the bloodstream. Once
in the cells, the glucose is used as the energy to fuel the cells doing their different
jobs or is stored in the liver or muscle cells as glycogen. This results in the
glucose level of the blood dropping, which then triggers the pancreas to switch
off the release of insulin.
What is the size of the liver and where is it located? The liver is your largest
internal organ. About the size of a football, it's located mainly in the upper right
portion of your abdomen, beneath the diaphragm and above your stomach, but
a small portion extends into the upper left quadrant. The liver is protected by the
ribs.
How does the liver function in relation to digestion? The liver has multiple
functions, but its main function within the digestive system is to process the
nutrients absorbed from the small intestine. Bile from the liver secreted into the
small intestine also plays an important role in digesting fat. In addition, the liver
is the body’s chemical "factory." It takes the raw materials absorbed by the
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intestine and makes all the various chemicals the body needs to function. The
liver also detoxifies potentially harmful chemicals. It breaks down and secretes
many drugs.
What are other functions of the liver in the body? Your liver processes blood,
breaking down the nutrients and chemicals your blood carries. It changes these
into forms that are easier for the rest of your body to use, and also regulates the
levels of most chemical in your blood.
What is the relationship between the liver and the gallbladder? Liver cells
produce bile, which flows into small channels called bile canaliculi. These small
channels drain into bile ducts. The ducts join to form larger and larger channels
and eventually form the left and right hepatic ducts, which join to form the
common hepatic duct. The common hepatic duct joins with a duct connected to
the gallbladder, called the cystic duct, to form the common bile duct. The
common bile duct is joined by the pancreatic duct just before it enters the small
intestine at the sphincter of Oddi.
What is the function of bile and where does it enter the digestive tract? Since
bile increases the absorption of fats, it is an important part of the absorption of
the fat-soluble substances, such as the vitamins A, D, E, and K. Besides its
digestive function, bile serves also as the route of excretion for bilirubin, a
byproduct of red blood cells recycled by the liver. Bile is a complex fluid
containing water, electrolytes and a battery of organic molecules including bile
acids, cholesterol, phospholipids and bilirubin that flows through the biliary tract
into the small intestine.
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
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