What is the excretory system?
The human excretory system is a group of organs which are specialised for the removal of certain excretory products
They include the lungs and kidneys
The liver also has a vital role in excretion
What is excretion?
Excretion is the removal of the waste substances of metabolic reactions (the chemical reactions that take place inside cells), toxic materials and substances in excess of requirements
Carbon dioxide must be excreted as it dissolves in water easily to form an acidic solution which can lower the pH of cells
This can reduce the activity of enzymes in the body which are essential for controlling the rate of metabolic reactions
For this reason, too much carbon dioxide in the body is toxic
Urea is also toxic to the body in higher concentrations and so must be excreted
main components of excretory system :
kidney - two bean shaped organs that filter the blood
ureter - tube connecting the kidneys to the bladder
bladder - organs that store urine , which is produced by the kidney
urethra - tubes that connects the bladder to the exterior
Why is urine important ?
How is urine formed in the kidneys?
What is the significance of maintaining the correct volume of extracellular fluid?
What are nephrons, and what is their function?
How does the body regulate the formation of urine?
What is the main waste product excreted by the skin?