The excretory system removes waste from the body through organs like the lungs, skin, kidneys, and liver. The kidneys act as filters for the blood, removing waste products like urea, salts, and water to produce urine. The liver converts toxic ammonia into less harmful urea, which is then filtered out by the kidneys. Urine is stored in the bladder and exits the body through the urethra. The excretory system is vital for removing different types of waste and keeping the body's chemical levels balanced.

2. What does it do?
 The body produces a number of different types of
wastes
 If not removed these can cause serious harm
 The job of this system is the removal of these
wastes…called EXCRETION

3. How does it work?
 In order for it to do its job properly this system must
use organs from other body systems
 Such as;
 Intestines
 Rectum
 Lungs
 Any others????

4. Waste Products
 Carbon dioxide – from oxygen being released by the
blood cells
 Ammonia – a VERY toxic compound caused from
protein breakdown by cells
 Urine – a result of chemical processes that create salt
and water as waste products

5. The Main Organs Involved
The Liver The Kidneys

6. The Liver
 Is involved in the digestive system as well
 Its primary job is to take the toxic ammonia produced
by the cells and change it to something less harmful
 It turns ammonia into UREA

7. The Liver
 Urea is far less toxic than ammonia, but it still needs to
be disposed of
 The liver releases the urea into the blood stream to
head towards its next filter point

8. The Kidneys
 Is the main organ in the excretory system
 It produces the urine for the body
 **They are the filters of the blood, they strain out all
the unwanted;
 Salts
 Water
 Urea

9. Kidneys
 Filters every drop of your blood about 300X a day;
 that’s once every 4 minutes
 During this filtering, urine is created by water, salt and
urea being pulled out
 Kidneys keep the water levels in your body balanced,
the more water you drink the more you urine you
create.

11. Ureters, Bladder and Urethra
 Ureters – Long tubes that connect the kidneys to the
bladder
 Urethra – Tube where the urine exits the body
 Bladder – Is a sac covered in muscle tissue that
expands when urine enters it.
 Can store about 1L or urine – When full muscles contract
and push out urine through the urethra

13. Your Skin
 Have you ever tasted Sweat?
 What does it taste like?
 Sugary? Sweet? Sour? Bitter? NO, its salty

14. Your Skin
 Your skin has thousands of tiny sweat glands just
below the surface
 These glands assist your body by helping to keep your
body cool (sweating)
 They also help by removing any excess salt

16. How does Urine Form?
 1. Blood enters the kidneys through the renal artery
 2. This artery splits into smaller and smaller vessels
 3. These small capillaries enter filtering units called
nephrons
 The kidney has millions of nephrons

17. How does Urine Form?
 4. These microscopic units remove the wastes from
blood and produce urine
 5. The “clean” blood returns to the body through the
renal vein
 6. Urine flows through a separate vessel and into the
ureter

18. Urine in Detection
 Several diseases have been detected by testing patients
urine samples
 Diabetes – detection of glucose (sugar) in the urine
because the kidneys have problems filtering it
 Sports athletes undergo urine tests before and after
competition to check for any illegal/banned
substances in their system.
 Olympics

20. Dialysis
 People with kidney or liver problems can lead normal
healthy lives due to dialysis
 It is a machine that will remove the wastes of the body
that the kidneys normal would remove
 The patients blood flows out of the person through a
special Selectively Permeable Membrane and them
back into the person – takes 4-6 hours, 3x a week