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Section 2 Workbook (units 4, 5 & 6) Name: Key KeyANANSWERAN__AN_________
C1. Analyze the functional inter-relationships
of the structures of the digestive
system.
1.
A) Complete the table
ANSWERS
Digestive System
Structure
mouth
tongue
teeth
salivary glands
pharynx
epiglottis
esophagus
cardiac sphincter
stomach
p yloric sphincter
duodenum
gall bladder
Function
Ingest food
Push food between the teeth; form the bolus; speech; taste; and spread saliva
Mechanical digestion; break food into smaller pieces for enzymes to act upon
Produces salivary amylase to start the digestion of carbohydrates (starch to maltose)
Muscular to push the bolus down the esophagus
Prevents food and drink from going down the esophagus
Directs food from the pharynx to the stomach by peristalsis
Controls what enters the stomach and prevents chyme from entering the esophagus
Mechanical digestion by churning food. Chemical digestion by pepsin to change
proteins into peptides
Slowly releases chyme into the duodenum
Where the majority of digestion occurs – final digestion of all macromolecules into
monomers. Receives enzymes from pancreas and wall of duodenum.
Stores bile until it is needed to emulsify fats
Regulates blood sugar levels with the hormones insulin and glucagon. Neutralizes
chyme (sodium bicarbonate) and makes enzymes for digestion SALT + N
First part = duodenum where majority of chemical digestion occurs to create monomers.
small intestine Last part is for absorption of monomers in the villi & microvilli
Lymph tissue to fight infection
pancreas
appendix
large intestine Absorbs mainly water. Also absorbs salts. Has E. coli to make vitamins, growth factors,
(colon)
rectum
anus
and folic acid.
Stores feces until elimination
Sphincter muscle for the release of feces
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B) Label all structures from the previous table on these diagrams.
Salivary glands
Liver
Stomach
Pancreas
Small Intestine
Large Intestine (colon)
Bile duct Pancreas Stomach Small intestine (duodenum) 2. Describe swallowing.
A reflex where the pharynx pushes the bolus to the esophagus and then, by peristalsis, the bolus is moved
to the stomach
3. Describe peristalsis
It is a wave of muscular contraction that moves food along the digestive tract.
4. What is the source gland for insulin? Pancreas
5. How does insulin maintain blood sugar levels?
It is a hormone that causes the cells of the body to take up glucose from the blood to decrease the blood
glucose levels
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6. Describe at least six functions of the liver. BBBBBB U
1 Makes bile
2 Breaks down and recycles old red blood cells
3 Makes blood proteins ex) albumin & fibrinogen
4 Monitors the blood nutrient levels
5 Makes urea
6 Regulates blood sugar levels with insulin and glucagon
7 Detoxifies blood ex) turns alcohol into fatty acids
7. Explain the role of bile in the digestion of fats.
Emulsifies fats – break fats into fat droplets (smaller pieces)
8. How is the small intestine specially designed for each of the following tasks?
a. Chemical digestion
Mucus to prevent digestion of the small intestine; glands to make intestinal juice with digestive enzymes; and an opening for receiving enzymes from the pancreas b. Physical digestion
Opening to receive bile from the gall bladder to emulsify fats c. Absorption
It has villi & microvilli to increase the surface area for absorption. It also is very long to allow for time needed for absorption of nutrients to occur 9. Describe and label the structures in this villus. Include the functions of the microvilli,
Trace the path way of all digestion products in to the villus.
Microvilli increase the surface area for absorption of nutrients and also release enzymes. Lacteal absorbs glycerol and fatty acids Blood capillaries absorb all other monomers -3-
10. Describe the functions of anaerobic bacteria in the colon.
They make vitamins, growth factors, and break down waste / feces (create the smell)
C2. Describe the components, pH, and digestive actions of salivary,
gastric, pancreatic, and intestinal juices.
11. A) Complete the table.
Enzyme
Optimal
pH
7
Salivary glands
8.5
Pancreas
Starch + water → maltose
2.5
Gastric glands in
stomach wall
Protein + water → peptides
8.5
Pancreas
Protein + water → peptides
8.5
Pancreas
Lipid + water → glycerol + fatty acids
Source Gland
Reaction Catalyzed
substrate + H2O → product
Starch + water → maltose
salivary amylase
pancreatic amylase
pepsinogen/pepsin
trypsin
lipase
8.5
Intestinal glands in Peptides + water → amino acids
wall of duodenum
8.5
Intestinal glands in Maltose + water → 2 glucose molecules
wall of duodenum
peptidase
maltase
8.5
Pancreas
Nucleic acids + water → nucleotides
nuclease
nucleosidases
8.5
Intestinal glands in Nucleotides + water → sugar, N-base, phosphate
wall of duodenum
B) Why is the enzyme pepsinogen secreted in an inactive form? What activates it?
So the stomach wall is not digested because it is a big protein bag. Pepsinogen is converted into pepsin by
hydrochloric acid - HCl
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12. Draw a graph to show the enzyme activity of pepsin and trypsin at various pH. Explain why the
curves are different.
Curves are different because the optimal pH for the enzymes is dependent upon where it is
released and acts in the body.
13. What is the importance of the pH level in the various regions of the digestive tract?
It is the optimal pH for enzymes to work at peak efficiency – enzymes have an optimal pH based upon
where they act in the body
14. Describe in detail the role of each of these substances.
Component
water in digestive juices
Role
Hydrolysis – necessary for the hydrolytic enzymes to
work.
Neutralizes the chyme from the stomach & raises the pH
sodium bicarbonate in pancreatic juice
to 8.5 so that the small intestine enzymes will function
2 functions
hydrochloric acid (HCl) in gastric
juice 3 functions
mucus in gastric juice 2 functions
Kills bacteria and pathogens, activates pepsinogen into
pepsin, denatures salivary amylase
Protects the lining of the digestive tract from enzymatic
reactions and keeps the food moving through the
digestive tract
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