Excretory System
What Life Process Does the Excretory
System Help to Accomplish?
What Organs Are Part of the Excretory
System?
Excretory System
 Includes the kidney, ureters, bladder and
urethra.
 Also called the urinary system
Excretory System
 Main organ: Kidney
 Function: You have
two kidneys that filter
wastes from the blood.
The wastes include
urea, excess water and
salts.
 The waste excreted is
called urine.
Nephron
 All diffusion
takes place in
the part of the
kidney called
the nephron.
Help for the Excretory System!
 Your liver plays a part in excretion.
Liver
 Cellular wastes containing nitrogen build up
in our bodies as ammonia. Ammonia is very
toxic!
 Our liver converts the ammonia to urea
which is carried in the blood plasma to the
kidneys where it is filtered our and excreted.
 What else do you know about the liver?
Help for the Excretory System!
 The skin plays a part in excretion.
Skin
 Your skin gets rid of excess water, salt and
urea through your sweat glands.
 The waste is called sweat.
 Adults produce between 0.5 and 10
liters/day.
 Sweating not only removes wastes it also
helps to keep your body cool, around 37
degrees C.
Help for the Excretory System!
 The lungs play a part in excretion.
The Lungs
 The lungs filter the cellular waste carbon
dioxide (CO2) from the blood stream.
 The blood carries this cellular waste to the
lungs. CO2 diffuses from a high
concentration in the blood to a low
concentration in the lungs.
 It is then exhaled and released from the body.
Questions:
 Where does the waste excreted by the
excretory system come from?
 Why isn’t feces included in our list of things
excreted from the body?
Malfunctions/Diseases
 Kidney Stones
 Kidney Failure
 Urinary Tract Infections