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Lesson 5 –
The Excretory
System
 It gets rid of wastes:

solid waste from digestion
(through the large intestine)
 carbon dioxide from cells
(through the lungs)
 It gets rid of wastes:
 liquid waste from cells
(through the kidneys, which
filter wastes out of the blood
and then produce urine)
 sweat (through the skin)
 Blood passes through the
kidneys 60 times a day.
 The kidneys remove substances
the body no longer needs and
returns substances it does need.
 Nephron – part of the kidney
where wastes are separated
from useful materials
 Wastes can build up to
dangerous levels.
 People with this problem need
dialysis, a treatment where a
machine does the job of the
kidneys.
 Through the urinary system:
 Urine is released from the
body.
 Through the skin:
 Sweat is released through tiny
openings in the skin called
pores.