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Science.7
The Excretory System
Name ___________________________
Date ____________________________
Notes
Essential Questions
1. Why do we urinate?
2. How does our body get rid of waste?
3. What is the function of the urinary system?
4. What are the major structures of the urinary system?
Vocabulary
urinary system, urine, ureters,
kidneys, bladder, urethra
Objectives
1. Identify the major structures of the excretory
system.
2. Identify the function of the excretory system.
The function of the excretory system is to: excrete wastes

Wastes that are removed include carbon dioxide, water, salt, urea, and uric acid

Most excreted wastes travel at some time in the blood.
The structures of the excretory system include:
Structure
Skin
How it Excretes Wastes
Through sweating
Type of Waste
Water, salt, urea, and uric acid
Exhaling
Carbon Dioxide, water
Produces urea, filters out harmful substances
Urea, breaks down alcohol and
alcohol related molecules
Defecating Solid waste
Feces (undigested foods)
Filters the blood for urea, minerals, water and salt
Urine
Lungs
Liver
Large Intestine
Urinary System
Urinary System Reading Questions:
1. List the structures of the urinary system.
 Kidney – filters the blood
 Ureter – connects the kidneys to the bladder
 Bladder – stores urine
 Urethra – tube that allows urine to pass out of the body
2. What is the role of the kidney and how many are there in the human body?
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3. Describe urine. What is it made of? How is it made?
4. Where does the CO2 that you breathe out with every exhale come from in the body? Explain fully. (Hint:
Starts at an organelle)
5. Thinking question: if the bladder is a muscle what type of muscle do you think it is? Explain your
reasoning. (Do you remember the 3 types of muscle?)
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