The excretory system removes waste from the body through various organs including the lungs, skin, colon and kidneys. The kidneys filter blood and produce urine by selectively reabsorbing useful substances and excreting waste like urea and salts. Urine travels from the kidneys through the ureters to the bladder for storage and then exits through the urethra. The main functions of the excretory system are to eliminate cellular waste and maintain chemical balance in the body. Diseases can occur if the system is not working properly, such as kidney stones, cystitis and renal insufficiency.

1. EXCRETORY SYSTEM

2. INDEX
5. Anatomy of Kidney
6. The Production of
Urine
7. Function of
Excretory System
8. Diseases of
excretory System
1.Excretion
2. Excretory Organ
3. Excretory Products
4. Urinary System

3. WHAT IS EXCRETION?
Excretion is the process of removing cellular
waste.
It is not removal of undigested material (
Egestion – removal of undigested food
matter )
 GOAL – Maintain homeostasis

4. There are four main excretory organs:
 Lungs
 Colon
 Skin
 Kidneys
mouth

5. Take Note !!
The liver is not an excretory organ, but
produces many products which are
excreted elsewhere.

6. LUNGS

7. COLON

8. SKIN

9. Renal Capsule
Protects kidney
Nephron
Medulla
Made up of pyramids
Pyramid
Made up of collecting ducts
Calyx
Collects urine from collecting
ducts
Papilla
Tips of each pyramid, fits into calyx
Renal artery
Carries blood to kidneys
Renal vein
Carries blood fromkidneys
Ureter
Carries urine from pelvis
to bladder for storage
KIDNEYS

10. EXCRETORY PRODUCTS
 Carbon
Dioxide
 Excess
Water
Excreted mainly via
Excreted mainly via

11. EXCRETORY PRODUCTS
Urea
Bile
Pigments
Excreted in the
faeces

12. URINARY SYSTEM
 The Urinary
System is a group
of organs in the
body concerned with
filtering out excess
fluid and other
substances from the
bloodstream.

13. PARTS OF URINARY
SYSTEM
 Kidney
 Ureters
 Bladder
 Urethra

14. KIDNEY
Kidneys 
they remove urea
and other waste
products from the
blood and form
urine.

15. Kidneys filter about 1700 liters of blood daily
in the average adult.
Average person loses 2l of liquid per day.

16. URETERS
 Ureters 
they carry
urine from the
kidney to the
bladder

17. BLADDER
 Bladder  it
stores urine
before it is
released from
the body. It
has a
muscular wall.

18. URETHRA
 Urethra  It
carries urine out
of the body.
• Men urethra is
common to the
reproductive
system
• Women
urethra is an
independant tube

19. THE ANATOMY OF THE KIDNEYS
 Blood enters the kidneys through the
renal arteries
 Each kidney is made up of thousands
of small functional units known as
nephrons. Each one of these
nephrons filters and purify the blood
independently.

20.  Glomerulus capsule
which contains lots of
blood capillaries
 Bowman’s capsule
surrounds the
glomerulus
 The tubules and
the loop of Henle
carry the urine to the
ureters

21.  Renal cortex 
Bowman’s capsules
 Renal medulla
loops of Henle
and collecting ducts
 Renal pelvis 
ducts which collect
the urine produced
by the nephrons.

22. THE PRODUCTION OF URINE
The formation of urine is a very
selective process.
 Urine contains:
 water
 toxic substances (urea, uric acid,
etc.)

23. urea
uric acid
ammonia

24. TAKE NOTE !!
The composition of
sweat is similar to
urine.
It is produced by
filtering the blood
that reaches the
skin.

25. FILTERING
1. Filtering:
Substances go
from the glomerulus to
the Bowman’s capsule

26. REABSORPTION
2.Reabsorption:
Water and
useful substances
go back from the
tubules to the blood

27. URINE
3. Urine
(water, urea,
uric acid, salts)
arrives to the
renal pelvis,
where reaches
the ureters.

28. URINE
Urine is a liquid produced by the
kidneys, collected in the bladder and
excreted through the urethra.

29. FLOW OF URINE
Glomerulus
Renal Tubules
Renal Pelvis
Renal Calices
Ureters
Renal cortex
Renal capsule
Renal medulla
Ureter
Renal vein
Renal artery
Nephron

30. THE FUNCTIONS OF THE
EXCRETORY SYSTEM
The primary function of the excretory system is:
To get rid of wastes
Eliminates useless by-products excreted from
cells
Eradicates harmful chemical build-ups
Maintains a steady, balanced chemical
concentration

31. DISEASES OF EXCRETORY SYSTEM
 Kidney
stones 
crystals of
uric acid

33. DISEASES OF EXCRETORY
SYSTEM
 Cystitis inflammation of the bladder
caused by a bacterial infection.

35. DISEASES OF EXCRETORY
SYSTEM
 Renal
insufficiency
kidneys do not
filter the blood
correctly and
waste products
are not removed
from the blood