Download 1.6 Digestive system

DIGESTION
Goal: Digestion takes place within a tube called the gut, which begins with the mouth and ends with the
anus. Digestion is an extracellular process. Food is broken down by digestive enzymes outside the
cells lining the digestive tract. It is essential the end products of digestion are small enough to pass
through the cells lining the gut. These food molecules are absorbed into the blood and taken to cells
where they are used for various functions. Read Chapter 14, pgs. 257-271 in “Inquiry into Life”, Mader 11th
edition, and using the following questions as a guide make notes on the following topics. You may be required to
access the internet or other resources to supplement your textbook.
The Digestive Tract
1. Define digestions two main processes
2. Provide the function of the following digestive organs:
a. oral cavity (mouth)
b. tongue
c. teeth
d. epiglottis (glottis)
e. pharynx
f. salivary glands
g. esophagus
h. cardiac sphincter
i. stomach
j. pyloric sphincter k. duodenum
l. small intestine
m. liver
n. gall bladder
o. pancreas
p. colon
q. appendix
r. rectum
s. anus
*you must also be able to identify these structures on a diagram*
.
3. Describe the following digestive processes:
a. emulsification
b. peristalsis
c. swallowing
4. Describe the effect of HCl on the following:
a. pepsinogen
b. stomach pH. Why is this pH necessary?
5. Explain how the small intestine is structurally designed for the absorption of
nutrients into the blood. Include a discussion of the villi, microvilli, capillaries
and lacteals in your explanation.
6. Contrast digestion and absorption in the small intestine.
7. Fully explain how the following hormones regulate the flow of digestive juices:
a. gastric b. GIP (gastric inhibitory peptide)
c. secretin
d. CCK (cholecystokinin)
8. Describe the role of the large intestine in the process of digestion.
9. Explain the function of E. coli in the large intestine.
Three Accessory Organs
1. Describe the function of the pancreas and gall bladder in the digestive
process.
2. List the four components of pancreatic juice, and describe the function of
each.
3. The gall bladder stores and releases bile.
a. Where is bile produced?
b. What are the components of bile and where do they originate from?
c. How does bile reach the intestine and what is it’s function in digestion?
4. Provide the seven functions of the liver.
5. Explain why the liver is considered a ‘gatekeeper’ to the blood? (Include the
importance of the hepatic portal vein)
Digestive Enzymes
1. Provide the source, and the digestive action of the following enzymes:
a. salivary amylase b. pepsin
c. pancreatic amylase
d. lipase
e. trypsin
g. peptidases
h. nuclease
f. maltase