Excretory
System
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
Organs of the Excretory System
• Kidneys = filter
blood that has
collected wastes
from cells
Organs of the Excretory System
• Kidneys = filter
blood that has
collected wastes
from cells
– Nephrons = filters
inside the kidneys
– Produce urine
(sterile waste fluid,
96% water)
Organs of the Excretory System
• Ureters = tubes that
lead from each
kidney to bladder
Organs of the Excretory System
• Urinary bladder =
muscular organ that
holds urine
Organs of the Excretory System
• Urethra = tube
that carries urine
from the bladder
out of the
body
Where is urine stored until the
body is ready to eliminate it?
1.
2.
3.
4.
Kidneys
Ureters
Bladder
Urethra
Functions of Excretory System
• Rids blood of
wastes (urea)
Functions of Excretory System
• Rids blood of
wastes (urea)
• Controls blood
volume by removing
extra water
produced by cells
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
Which is not a function of the
excretory system?
1. Removes wastes
2.
3.
4.
from the blood
Removes excess
water from the blood
Removes carbon
dioxide from the
blood
Removes excess salt
from the blood
Other Excretory Organs
• Skin = releases perspiration (water
and salts) to cool off the body
Other Excretory Organs
• Lungs = release carbon dioxide from
the body
Which system does not include an
excretory organ?
1. Excretory system
2. Integumentary
system
3. Cardiovascular
system
4. Respiratory
system
Excretory System
• How did the Filter It investigation model
our excretory system?
• What are some advantages of the model?
• What are some limitations of the model?