EXCRETORY SYSTEMS
CONTENT
- Definition of Excretory Systems
- The Need for Excretion
- Contractile Vacuoles
- Flame Cells in Flatworm
- Malpighian Tubules in Insects
- Kidneys in Vertebrates
- Other Excretory Organs in Mammals
- Stomata and Lenticels
Definition of Excretory Systems
Excretory systems refer to all the cells and organs of any living organism which enables it to eliminate harmful substances away from the body.
Excretion is therefore the removal of toxic wastes of metabolism from the body of living organisms.
The Need for Excretion
Waste products produced in the body by excretion must not be allowed to remain in the because of the following reasons:
- Waste products when not removed can interfere with normal metabolic activities of the body.
- Excretion helps to maintain salt and water balance i.e. homeostasis in the body.
- Some products are poisonous and must never be allowed to accumulate within the body.
- The excretory products are harmful to the body and so must be removed.
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