PMR Form 3 Science Chapter 3 Excretory system

2. Chemical Processes in the Body
Use up
Oxygen
Glucose
Amino Acids
Water
Nutrients
Produce
Carbon dioxide
Water
Urea
Heat Water, Mineral salts, Urea, Carbon Dioxide, Heat
Toxic Chemicals

3. Excretory Organs in Human
Urinary System Lungs Skin
Why waste products
must be excreted out of
the body???
Liver

5. 2

8. Location of the Kidney

9. Kidney Function
• Detoxify blood
• Increase calcium absorption
– calcitriol
• Stimulate RBC production
– erythropoietin
• Regulate blood pressure and electrolyte
balance
– renin

10. Structure of the Urinary System
• 2 Kidneys
• 2 Ureters
• Bladder
• Urethra

11. The Blood Supply to the
Kidney

15. The Urinary System

16. Filtration system
in the Kidney
Filtration
Mineral salts
Sugar
Amino Acids
Waste-Urea
Reabsorption
All Sugar
All amino acids
Mineral Salts
Water

17. Function of the Kidney
• Filter blood in order to remove cellular
waste products from the body.
• Maintain chemical composition, pH and
water level
• At any given time, 20 % of blood is in the
kidneys. Humans can function with one
kidney.
• If one ceases to work, the other
increases in size to handle the workload.

18. Cellular waste
• urea
– (a nitrogenous waste produced in the liver from
the breakdown of protein. It is the main
component of urine)
• uric acid
– (usually produced from breakdown of DNA or
RNA)
• creatinine
– (waste product of muscle action).

19. Composition of Chemicals in the Body
Substance Blood in renal Kidney Urine
artery tubules (filter
system)
Glucose 2.0 2.0 0
Mineral salts 10.0 10.0 17.0
Amino acids 0.9 0.9 0
Protein 88.0 0 0
Urea 0.5 20.0 20.0
RBC & WBC 47% 0% 0

20. Kidney failure
• Urinary Tract Infection
• Kidney Stone
• Kidney Infection
• Diabetic Nephropathy
• Hypertension
• Glomerulonephritis
• HIV nephropathy

21. Kidney Stone

22. Treatment of Kidney Failure
-Dialysis-
• ½ of patients with kidney disease eventually
require dialysis
• Diffuse harmful waste out of body
• Control BP
• Keep safe level of chemicals in body
• If dialysis cannot work, the patient has to
undergo kidney transplant

23. Hemodialysis
• 3-4 times a week
• Takes 2-4 hours
• Machine filters
blood and
returns it to
body

24. Peritoneal Dialysis
• Abdominal lining filters blood
• 3 types
– Continuous ambulatory
– Continuous cyclical
– Intermittent