The excretory system deals with removing the waste and toxic substances from the body.
The excretory system of human beings consists of the following organs : two kidneys, two ureters, a bladder and a urethra.
Kidneys - They are the bean shaped organs involving in the filtration of blood.
Ureter - They are tube like structures that connects the kidney to bladder.
Bladder - The bladder stores the urine before it leaves the body.
Urethra - It is the tube like structure that carries the urine from the body to outside.
Urine Formation:
Nephrons are the functional unit of kidney.
The blood that contains urea and other waste products passes through nephrons in the kidneys.
The nephrons filter this blood and remove the urea and other undesirable substances from it.
Tubules are responsible for absorption and reabsorption of ions and molecules such as sodium ions, glucose, amino acids, water etc.
A large amount of water is reabsorbed from the filtrate by the collecting duct.
The liquid that is left in the kidneys appears as a yellowish-liquid called urine and is composed of urea, other waste substances as well as excess water.
