1. The Excretory System
Vocabulary
Foundation Science SC 22101

2. The Excretory System
Digestive
System

3. The Excretory System
Excretory
System
Digestive
System

4. Function of the Excretory System
1) To get waste and toxins out of body.
2) Helps keep the correct amount of
water and ions in the body.

5. Function of the Excretory System
1) To get waste and toxins out of body.
2) Helps keep the correct amount of
water and ions in the body.
An ion is an atom or
molecule with a positive
(+) or a negative (-)
charge.

6. Homeostasis
Homeostasis is the body keeping stable.
If you have too much of something in your
body, you will NOT be in homeostasis.
Your excretory
system allows
your body to stay
in a state of
homeostasis.

7. Osmoregulation
Osmoregulation is moving of ions across
membranes to keep the right amount
of water (=to keep homeostasis).
1) Hypotonic solutions are when there are many
ions inside a cell, and water will go IN.
2) Isotonic solutions are when water will neither go
in or out.
3) Hypertonic solutions are when there are many
ions outside a cell, and water will go OUT.

8. Copy Diagram in Notebooks
Water will rush into
the cell, making it swell
(get bigger).
Water will rush OUT of
the cell.
Don’t gain or lose water
Ions

9. Osmosis
Osmosis is water moving from an area of
higher concentration to an area of lower
concentration.

10. Testing – 1, 2, 3…..
A fish is swimming in
saltwater. Which
way will water
want to move (in
or out of the
fish)?

11. A fish is swimming in
saltwater. Which
way will the fish’s
water want to
move? OUT
Would the saltwater
be considered
hypertonic or
hypotonic?
Testing – 1, 2, 3…..

12. A fish is swimming in
saltwater. Which
way will water
want to move (in
or out of the
fish)? OUT
Would the saltwater
be considered
hypertonic or
hypotonic?
Testing – 1, 2, 3…..

13. A fish is swimming in
FRESHWATER.
Which way will
the fish’s water
want to move?
Testing – 1, 2, 3…..

14. Testing – 1, 2, 3…..
A fish is swimming in FRESHWATER. Which way
will water want to move? IN
Would the freshwater be considered hypertonic
or hypotonic?

15. A fish is swimming in FRESHWATER. Which way
will water want to move? IN
Would the freshwater be considered hypertonic
or hypotonic?
Testing – 1, 2, 3…..

16. 1) What does “homeo”
mean in Greek?
2) What does “hyper”
mean in Greek?
3) What does “iso”
mean in Greek?
4) Which one of our
vocabulary words
best describes what is
happening when you
wipe water off your
body with a towel?
5) If you get into a
bathtub filled with
freshwater, is the
water a hypertonic or
hypotonic solution
compared to your
body (will water go
into or out of your
body)?
Questions
6) Do you think a saltwater fish would live if you put it into
freshwater?
7) How do you think saltwater fish get the freshwater they need?
8) What is a semi-permeable membrane?