1. JH-KEADLE
The Excretory System

2. procedure 1. Mix a teaspoon of dirt and 150 mL of water in
a beaker. Stir the mixture until most of the dirt
is dissolved.
2. Add food coloring to the beaker.
3. Stir the mixture until all is mixed.
4. Layer a coffee filter over the neck of a second beaker and secure with a rubber band.
Do not pull filters tightly across the top. Allow them to dip a little.

3. procedure
5. Pour the dirt and water mixture onto the filter paper. Pour slowly and carefully so as not to overflow the filter. 6. In your spiral, describe what is happening in the demonstration.

4. The nephron Using the laptops, look up an image of a nephron.
Draw a picture of the nephron in your spiral.

5. Excretory System Why do our bodies need to filter waste from the body?
Maintain homeostasis
Removal of harmful materials
Removal of excess fluids, chemicals, minerals, vitamins, salts, and other wastes from the blood

6. Excretory System Organs kidneys ureters urinary bladder urethra lungs
skin

7. Organs of the Excretory System
sweat glands
lungs

8. Functions of Excretory System
Rids blood of
wastes (urea)
Controls blood
volume by removing
extra water
produced by cells
Balances salts and
water so cells can function properly

9. Organs of the Excretory System
kidneys – major organs of the excretory system that filters blood and eliminates urea, excess water, and other wastes

10. Organs of the Excretory System

11. Organs of the Excretory System
ureters – two narrow tubes that urine flows through to get to the bladder

12. Organs of the Excretory System
urinary bladder – sac-like, muscular organ that stores urine

13. Organs of the Excretory System
urethra – tube that urine travels to leave the body

14. Other Organs of Excretion
There are other organs in our body that can excrete substances
Lungs – carbon dioxide and water
Skin – sweat, water, some chemicals
Liver – breaks down molecules, recycles hemoglobin and turns it into bile

15. The Filtering Process
Every drop of blood in your body passes through the kidneys and is filtered 300 times a day
nephrons – tiny structures
that filter blood in the
kidneys

16. Filtering Out Waste
After entering the kidneys, blood flows through smaller and smaller arteries
The blood eventually reaches a cluster of capillaries called nephrons
In the nephron, urea, glucose, other chemicals, and some water move out of the blood and into the nephron

17. Filtering Out Waste Blood cells and proteins stay in the capillaries
Glucose, water, and small amounts of other substances are reabsorbed into the blood stream
Urea and other wastes stay in the nephrons

18. Filtering Out Waste The liquid left in the tube is urine
The urine moves down the ureters and into the bladder
When the bladder is full, you feel the urge to urinate

20. Filtering Summary 1. both wastes and needed materials are
filtered out of the blood
2. the needed material is returned to the
blood
3. the waste is eliminated in the urine

21. Analyzing Urine Some medical problems can be found by testing urine
Glucose – diabetes
Protein – kidney failure
Drug residue – drug abuse

22. Which is not a function of the excretory system?
Removes wastes from the blood
Removes excess water from the blood
Removes carbon dioxide from the blood
Removes excess salt from the blood

23. Which system does not include an excretory organ?
Excretory system
Integumentary system
Cardiovascular system
Respiratory system

24. Where is urine stored until the body is ready to eliminate it?
Kidneys
Ureters
Bladder
Urethra

26. Body systems that work with the excretory system;
circulatory system to carry waste to the kidneys
respiratory system to remove carbon dioxide
integumentary system to remove salt

27. Comparing Cells to Body
What cell organelle helps to break down waste?
lysosomes
What cell organelle packages waste?
golgi body