Excretory system.

2. Unit 3(D): The excretory system.

3. HOW WE PERFORM EXCRETION
We excrete …………..
through our lungs. We
excrete the residues of ………
through the anus. To excrete
other substances we use our
urinary system and sweat
glands.

4. HOW WE PERFORM EXCRETION
We excrete carbon dioxide
through our lungs. We excrete
the residues of the food
through the anus. To excrete
other substances we use our
urinary system and sweat
glands.

5. EXCRETION
is the expulsion of residues.

6.  We expel residues :
in URINE, through the
urinary system
in SWEAT through the
sweat glands.

7. Organs of the Human Urinary System
1. THE KIDNEYS are organs which filter the
1. THE KIDNEYS are organs which filter the
blood. They extract toxic substances and
blood. They extract toxic substances and
form urine.
form urine.

8. 2.-THE URINARY TRACT is the tube through
which urine flows out of our bodies. It
includes:
 THE URETERS
 THE BLADDER
 THE URETHRA

9. THE RENAL VEINS AND THE RENAL
ARTERIES.

11. HOW THE URINARY SYSTEM WORKS
→Blood containing residues flows to the
KIDNEYS through the RENAL ARTERIES.
→Each KIDNEY filters the blood and extracts
waste products.
→The clean blood returns to the body
through the RENAL VEINS.
→The residues are mixed with water to form
urine which flows out of the KIDNEYS
through the URETERS. It collects in the
BLADDER.
→When the BLADDER is full we expel the
urine through the URETHRA.

12. Dialysis

13. EXCRETION THROUGH THE
SKIN
OUR SKIN has million of SWEAT GLANDS which
produce sweat.
1.- Blood filled with waste products flows to the sweat
glands through capillaries.
2.- The sweat glands filter the residues, mix them with
water and expel them as sweat through the pores in
the skin.
3.- The clean blood retursn to the body through the
capillaries.

14. SWEAT
GLAND