1. Review Questions
1) What is osmosis?
2) Does a saltwater fish lose water from
its body, or gain water?
3) Is saltwater a hypertonic or hypotonic
solution for the fish?
4) Is your body in homeostasis right now?
5) Try to guess what the most important
organ on a fish is for its
osmoregulation.
6) What is a semi-permeable membrane?

2. Student Question
1) How can an octopus know what
color to change to?
They do this using chromatophore and
iridophore cells. Iridiphore cells can
reflect what is beneath the octopus. I
think these are voluntary AND
involuntary responses.

3. Lesson 3: Human Excretory
System Organs and Function
Foundation Science SC 22101

4. Human Excretory System Organs
1) Kidneys
2) Skin
3) Lungs
4) Ureters
5) Urinary Bladder
6) Urethra
7) Liver*
*Not really an excretory system
organ

5. Human Excretory System Organs
The kidneys’ job is
to take waste
out of the
bloodstream.
They do this by
making urine.

6. Human Excretory System Organs
The kidneys’ job is
to take waste
out of the
bloodstream.
They do this by
making urine.
Real kidney

7. Human Excretory System Organs
Kidneys also keep
the correct
amount of ions
outside of the
body’s cells so
the body can
maintain
homeostasis.

8. How do the
Kidneys Work?
1) Blood with toxins in
it is brought to the
kidney by the aorta
artery (red).
Kidney

9. How do the
Kidneys Work?
1) Blood with toxins in
it is brought to the
kidney by the aorta
artery (red).
2) Toxins are taken out
of the blood and
made into urine
which empties to
the bladder in
ureters.
Kidney

10. How do the
Kidneys Work?
1) Blood with toxins in
it is brought to the
kidney by the aorta
artery (red).
2) Toxins are taken out
of the blood and
made into urine
which empties to
the bladder in
ureters.
3) Clean blood is then
sent out of the
kidney in the vena
cava vein (blue).
Kidney

11. Draw and
Label
Use BLUE and RED!
Label the kidney,
aorta, vena cava,
renal arteries and
veins, ureters, and
bladder.

12. How Does the Kidney Take Out the
Toxins?
When the dirty
blood enters
the kidney it
passes through
units called
nephrons.
As the blood passes
through each
glomerulus
filter, water
and waste is
taken out.

13. How Does the Kidney Take Out the
Toxins?
When the dirty
blood enters
the kidney it
passes through
units called
nephrons.
As the blood passes
through each
glomerulus
filter, water
and waste is
taken out.
What is your
urine made
from??

14. How Does the Kidney Take Out the
Toxins?
When the dirty
blood enters
the kidney it
passes through
units called
nephrons.
As the blood passes
through each
glomerulus
filter, water
and waste is
taken out.
What is your
urine made
from??
Waste from
Blood!

15. Picture
Showing
Blood Vessels
Taking Blood
In and Out of
the Kidney

16. Picture
Showing
Glomerulus
Filters in a
Nephron

17. How the Kidney Gets Waste Out…….

18. Ureters
The urine (waste)
collects, goes
down the
ureters and
into the
bladder.

19. Ureters
Ureter function:
to bring the
waste from
blood (=urine)
to the bladder.

20. Bladder
The bladder stores
the urine.

21. Bladder
The bladder stores
the urine.
Empty Bladder
Full Bladder

22. Urethra
Carries blood from
the bladder.
In males, the
urethra ends at
the tip of the
penis. In
females, the
urethra ends
near the
opening of the
vagina.
Kidney

23. Urethra
Go back and put
a female
urethra on
your
drawing.
Kidney

24. Lungs
Lungs absorb oxygen for
respiration.
Carbon dioxide is a
byproduct of
respiration. The lungs
expel carbon dioxide.
This is why lungs are
part of the excretory
system.

25. Lungs
-Oxygen comes into the
trachea, and then into
the lungs through
bronchus and
bronchioles.

26. Lungs
-Oxygen comes into the
trachea, and then into
the lungs through
bronchus and
bronchioles.
-Oxygen then moves to
alveoli. Blood vessels
around the alveoli
then transport the O2
for respiration.

27. Alveoli in the Lungs
-The carbon
dioxide
made during
respiration
then returns
back to
alveoli
where it is
absorbed
and
exhaled.

28. Review
Alveoli
With
Picture

29. Draw a ball of
alveoli with its
blood vessels.
Show arrows
() with
blood coming
IN and OUT.
Show which
blood has O2
(veins), and
which blood
has CO2
(arteries).

30. Breathing
-Inhale oxygen
-Exhale CO2 made
during
respiration
What is
respiration?

31. Breathing
-Inhale oxygen
-Exhale CO2 made
during
respiration
What is
respiration?
It is the release of
energy from
nutrients and
O2 in the cells.

32. Skin
Skin is the largest organ in the
body.
Why is the skin part of the
excretory system?

33. Skin
Skin is the largest organ in the
body.
Why is the skin part of the
excretory system? Sweat.
Water, urea and salt are excreted
in sweat.

34. Skin
Skin is the largest organ in the
body.
Why is the skin part of the
excretory system? Sweat.
Water, urea and salt are excreted
in sweat.
Epidermis – outer layer of skin
protects the body from
bacteria. (the outer layer of
your epidermis is dead skin,
this is where most of the
dust in your house comes
from).

35. Skin
Skin is the largest organ in the
body.
Why is the skin part of the
excretory system? Sweat.
Water, urea and salt are excreted
in sweat.
Epidermis – outer layer of skin
protects the body from
bacteria. (the outer layer of
your epidermis is dead skin,
this is where most of the
dust in your house comes
from).
Dermis – this layer is alive and
contains blood vessels and
sweat glands.

36. Liver?....
Liver turns ammonia into urea.
Also helps remove poisonous substances like mercury from body.
Liver is considered a digestive system organ, but plays an important role
in excretion as well.

37. Questions (can use phone)
1) How do the kidneys filter blood?
2) What job do the lungs perform in eliminating waste from the body?
3) What is in sweat?
4) Name 3 ways that wastes are taken out of the body.
5) Books like to color arteries _________, and veins _________. Which color carries
oxygen?
6) Oxygen travels into bronchioles, then into __________ where it is absorbed into the
bloodstream.
7) Carbon dioxide is brought to the lungs by ____________ where it is then absorbed by
alveoli and exhaled by the lungs.
8) Name one difference between an artery and a vein.
9) What is the main artery that supplies the kidneys with “dirty” blood called?
10) A car has an oil filter to clean its oil : A nephron has a __________ to clean its blood.
11) Your _________converts ammonia into urea. The urea is then moved down by the aorta
to your ___________ where it is taken out of the bloodstream by _________.
12) Name 2 places that urea can be excreted from the body.
13) What is the job of alveoli?
14) Explain the difference between a nephron and a glomerulus.
15) What part of the body does respiration take place?