The Excretory System
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Printed: September 4, 2015
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C HAPTER
Chapter 1. The Excretory System
1
The Excretory System
Lesson 19.2: True or False
Name___________________ Class______________ Date________
Write true if the statement is true or false if the statement is false.
1.
2.
3.
4.
5.
6.
7.
_______ Organs of excretion include the large intestine and sweat glands in the skin.
_______ Blood containing wastes enters each kidney through a ureter.
_______ All of the water filtered out of the blood in the kidneys is excreted in urine.
_______ The process of urination is normally under conscious control.
_______ The kidneys filter all of the blood in the body once a day.
_______ One function of the kidneys is to help keep blood pressure within a normal range.
_______ You need both kidneys to live a normal, healthy life.
Lesson 19.2: Critical Reading
Name___________________ Class______________ Date________
Read this passage based on the text and answer the questions that follow.
Excretion is any process in which excess water or wastes are removed from the body. Excretion is the job of the
excretory system. Besides the kidneys, other organs of excretion include the large intestine, liver, skin, and lungs.
The large intestine eliminates solid food wastes that remain after digestion takes place. The liver removes excess
amino acids and toxins from the blood. Sweat glands in the skin excrete excess water and salts in sweat. The lungs
exhale carbon dioxide and also excess water as water vapor.
The kidneys are the main organs of excretion. Their main function is to filter waste products and excess water from
the blood and excrete them from the body as urine. The kidneys help the body maintain homeostasis by filtering all
the blood in the body many times each day and producing urine. They control the amount of water and dissolved
substances in the blood by excreting more or less of them in urine. The kidneys also secrete hormones that help
maintain homeostasis. For example, they produce a hormone that stimulates bone marrow to produce red blood cells
when more are needed. They also secrete a hormone that helps regulate blood pressure and keep it within a normal
range.
Questions
1. What is excretion? Identify three organs of the excretory system (other than the kidneys), and state their
functions.
2. How do the kidneys help maintain homeostasis as organs of excretion?
3. Explain two other ways the kidneys help maintain homeostasis.
Lesson 19.2: Multiple Choice
Name___________________ Class______________ Date________
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Circle the letter of the correct choice.
1. Excess water is removed from your body when you
a.
b.
c.
d.
urinate.
exhale.
sweat.
all of the above
2. The urinary system includes all of the following organs except the
a.
b.
c.
d.
liver.
ureters.
urethra.
urinary bladder.
3. How many nephrons does each kidney contain?
a.
b.
c.
d.
fewer than 10
around 100
about 1,000
more than 1,000,000
4. Clean blood leaves a kidney through a(n)
a.
b.
c.
d.
artery.
capillary.
urethra.
vein.
5. Urine moves through the ureters by
a.
b.
c.
d.
gravity.
diffusion.
peristalsis.
none of the above
6. How do the kidneys help maintain homeostasis?
a.
b.
c.
d.
They control the amount of water in the body.
They secrete a hormone that regulates sweat production.
They secrete a hormone that stimulates muscle contractions.
all of the above
7. How does untreated diabetes cause kidney failure?
a.
b.
c.
d.
It leads to kidney stones that damage nephrons.
It damages capillaries in the kidneys.
It causes frequent urinary tract infections.
It causes urine to back up in the kidneys.
Lesson 19.2: Matching
Name___________________ Class______________ Date________
Match each definition with the correct term.
Definitions
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1.
2.
3.
4.
5.
6.
7.
Chapter 1. The Excretory System
_______ muscular tube that carries urine out of the body
_______ tiny structure in a kidney that filters blood and forms urine
_______ sac-like organ that stores urine
_______ mineral crystal that forms in urine inside a kidney
_______ artificial filtering of blood through a machine
_______ muscular tube that carries urine from a kidney to the urinary bladder
_______ main organ of the urinary system
Terms
a.
b.
c.
d.
e.
f.
g.
ureter
kidney stone
nephron
urethra
kidney
hemodialysis
urinary bladder
Lesson 19.2: Fill in the Blank
Name___________________ Class______________ Date________
Fill in the blank with the appropriate term.
1.
2.
3.
4.
5.
6.
7.
_____ is any process in which excess water or wastes are removed from the body.
The _____ are a pair of bean-shaped organs on each side of the body just above the waist.
Organs of the _____ system include the kidneys, liver, and lungs.
The main function of the kidneys is to filter blood and form _____.
The part of each nephron called the _____ is where blood is filtered.
The part of each nephron called the _____ is where excess water and wastes are collected.
The process of urine leaving the body is referred to as _____.
Lesson 19.2: Critical Writing
Name___________________ Class______________ Date________
Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.
Describe the organs of the urinary system, and explain the function of each organ in excretion.
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