1. Cells & Systems
The Excretory System

2. What does it do? Our body produces a bunch of different waste products
If they were to build up we could get seriously sick or worse
Enter the excretory system!
The system responsible for waste removal

3. Waste Products Example we’ve covered already…
What waste product do we breath out?
CO2
Digestive system breaks down protein we are left with ammonia
This is very toxic!
Ummkay?
I am ammonia!!
Noooo!!
Help!!

4. I’m Britney Spears. I don’t understand science. Don’t ask me!
Waste Products Cont …
We also have processes that create …
Excess water
Excess salt
Solid waste (poop)
Etc …
So how do we break them down and get rid of them?
GROSS!!!!
I’m Britney Spears. I don’t understand science. Don’t ask me!

5. The Organs The Liver Main role is the digestive system
Enzyme release, filter, etc …
In the excretory system it takes the toxic ammonia out of the blood stream
Converts the ammonia to a substance called urea
Puts the less harmful urea back into the bloodstream

6. The Organs

7. The Organs

8. The Organs

9. The Organs

10. The Organs

11. The Organs

12. The Organs Cont … The Kidneys A filter site for the body
Approx 10cm long & you have 2
Filter blood of unwanted/unneeded
Urea
Water
Salts
They produce urine (pee!)

13. The Organs Cont …

14. The Organs Cont …

15. The Organs Cont …

16. The Organs Cont … Interesting kidney facts … Why do we filter so much?
Every drop of blood in your body on a given day is filtered about 300 times
This means about 180L of blood passes through kidneys each day
On average you produce 1.5L of urine per day
Why do we filter so much?

17. How do I make pee? 1) Blood enters kidney via renal artery
2) Artery branches to smaller & smaller vessels
3) Now in capillaries they enter the filter units called nephrons! We have millions of them
4) Nephrons remove waste & produce urine
5) Clean blood goes back into system via renal vein
6) Waste (urine) goes down ureter

18. How do I make pee?

19. How do I make pee?

20. Ureters & Bladder & Urethra
Ureters are long tubes
Connect kidneys to bladder
The bladder is sac covered in muscle tissue
Urine enters bladder it expands
Can hold 1L of urine
The muscles contract and push the urine out through the urethra

21. Ureters & Bladder & Urethra

22. The Skin Has anyone ever tasted their sweat?
What does it taste like?
Below the surface of your skin there are 1000s of tiny sweat glands
What does sweat do?
Keeps you cool
Removes excess salt

23. The Power of Urine Urine can tell you if you have certain diseases
Diseases that for example affect how the kidneys function
Could have protein in urine because filtration is not happening correctly
Glucose in the urine if you have diabetes
The Power of the Nose

24. Dialysis
If your kidneys do not work properly medicine has invented a machine to do the work for you
Dialysis Machine
It can remove the waste from the blood just as your kidney would
So how does it work?

25. Dialysis Cont… During dialysis
Your blood enters a special tubing inside the machine
The tubing is selectively permeable
The tube is surrounded by fluid
Waste diffuses out of the blood into the fluid while certain substances diffuse back into the blood from the fluid
Clean blood pumped back into patient
Can take 4-6 hours to fully clean the blood

26. Cells & Systems
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