Excretory System

1. THE EXCRETORY SYSTEM
Chapter 4 Section 2

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3. FUNCTIONS OF EXCRETORY SYSTEM
Eliminate wastes from the body.
It is a combined effort of…

4. URINARY SYSTEM
Rids blood of wastes
produced by the cells
Controls the blood
volume by removing
excess water produced
by body cells during
respiration.

6. REGULATING FLUID LEVELSHypothalamus
The Hypothalamus is constantly monitoring how
much fluid is in the body and is always sending out a
hormone that controls the amount of fluid. Hormone

7. REGULATING FLUID LEVELSHypothalamus
How much fluid is in this body?

8. Hypothalamus REGULATING FLUID LEVELS
Too Much!! Hormone

9. REGULATING FLUID LEVELS Hormone
When there is too much fluid in the body, the
hypothalamus send out less hormone which tells the
kidneys to…
Return less water to blood
Increase the amount of
wastewater, called urine. Hypothalamus

10. Hypothalamus REGULATING FLUID LEVELS
Not enough!! Hormone

11. REGULATING FLUID LEVELS
When there is not enough fluid in the body, the
hypothalamus send out more hormone which tells
the kidneys to…
Return more water to your blood (which decreases
the amount of urine) Hypothalamus Hormone

13. Located on the back wall of the abdomen at about
waist level
Filter blood that contains wastes collected from
cells
Red-brown colour is due to the enormous blood
supply
How longs does it take all the blood in your body
to filter through the kidneys????
5 minutes!!!
ORGAN OF THE URINARY SYSTEM - KIDNEYS

14. ORGAN OF THE URINARY SYSTEM - KIDNEYS

15. Blood enters
the kidneys
through a large
artery and
leaves through
a large vein.

16. FILTRATION IN THE KIDNEYS
There are about 1 million tiny filtering units
called nephrons.
A nephron is a
cuplike structure
and a tube-like
structure called
a duct.

18. Filtration in the kidneys happens in two stages.
The first filtration:
Blood moves from a renal artery to capillaries
in the cuplike structure.
Water, sugar, salt, and
wastes from the blood pass
into the cuplike structure.
Red blood cells and proteins
are left behind in blood.
FILTRATION IN THE KIDNEYS

19. Liquid in the cuplike structure is squeezed
into a narrow tubule.
Capillaries that surround the tubule perform
the second filtration.
Most of the water, sugar,
and salt are reabsorbed and
returned to the blood.
These capillaries merge to
form small veins, which
merge to form a renal vein
in each kidney.
FILTRATION IN THE KIDNEYS

20. Purified blood is returned to the circulatory
system.
The liquid left behind flows into collecting
tubules.
This wastewater, urine,
contains excess water, salts,
and other wastes that are
not reabsorbed by the body.
An average person produces
1L of urine per day.
FILTRATION IN THE KIDNEYS

22. URINARY SYSTEM
Urine in the collecting
tubule drains into a
funnel-shaped area
that leads to each
ureter
The ureter is a tube
that leads from the
kidneys to the bladder.
The bladder is a
muscular organ that
holds urine until it
leaves the body.

23. URINARY SYSTEM
The walls of the
bladder are elastic,
they can stretch and
hold up to 0.5 L of
urine.
When empty, it looks
wrinkled and the cells
lining the bladder are
thick.

24. URINARY SYSTEM
When full, it looks like
an inflated balloon
and the cells are
stretched and thin.
The urethra carries
urine from the
bladder to the outside
of the body.

25. GAINING AND LOSING WATER
How does your body gain water?
SourceAmount (mL) Percent
Oxidation of nutrients250 10
Foods 750 30
Liquids 150 60
Total 2500 100

26. GAINING AND LOSING WATER
How does your body lose water?
SourceAmount (mL) Percent
Urine 1500 60
Skin 500 20
Lungs 350 14
Feces 150 6
Total 2500 100

27. URINARY DISEASES & DISORDERS
If your kidneys are not working, then……
Waste products are not removed, then build
up and acts as a poison in body cells
Sometimes fluids also build up around the
heart, causing it to work harder to move
blood to lungs
Water accumulates and causes swelling of
ankles and feet

28. When no excretion is happening……
An imbalance of salts occurs in the body and
the body tries to restore this balance.
If it is not restored, the kidneys and other
organs can be damaged.
Kidney failure occurs when the kidneys do
not function properly.
This is NOT good because the job of the
kidney is so important to the rest of the
body.
URINARY DISEASES & DISORDERS

29. What if there is an infection……
An microorganism infection usually begins in
the bladder
It can spread to the kidneys
Most of the time, it can be cured with
antibiotics
URINARY DISEASES & DISORDERS

30. When a ureter or urethra is blocked……
Urine cannot flow out of the body properly.
If the blockage is not corrected, the kidneys
can be affected.
URINARY DISEASES & DISORDERS

31. Detecting a disease or disorder….
Urine can be tested.
Change in colour can suggest liver or
kidney problems.
Increases amounts of albumin (a
protein) can indicate kidney disease.
High levels of glucose can indicate
diabetes.
URINARY DISEASES & DISORDERS

32. A person can live with only one kidney.
The one kidney will increase in size and works
harder to make up for the loss of the other kidney.
If a person is missing both kidneys can still live, but
has to have their blood filtered by an artificial
kidney machine. This process is called dialysis.
URINARY DISEASES & DISORDERS

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