Form 3 PMR Science Chapter 3 Excretory System

1. Chapter 3
Excretory System

2. Chemical Processes in the
Use up
Body
Oxygen
Glucose
Amino Acids
Water
Nutrients
Water,
Produce Mineral salts,
Carbon dioxide Urea,
Water Carbon Dioxide,
Urea Heat
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
o calcitriol
• Stimulate RBC production
o erythropoietin
• Regulate blood pressure and electrolyte balance
o renin

10. Structure of the Urinary System
• Two
Kidneys
• Two
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
o (a nitrogenous waste produced in the liver from the breakdown of
protein. It is the main component of urine)
• uric acid
o (usually produced from breakdown of DNA or RNA)
• creatinine
o (waste product of muscle action).

19. Composition of
Chemicals in the Body
Substance Blood in Kidney Urine
renal 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
o Continuous ambulatory
o Continuous cyclical
o Intermittent