4th Class Science Our Body Excretory System

     Excretory system

Excretory system throws out waste from our body. Human excretory system consists of kidneys, ureter urinary bladder and urethra.

      Excretory System

We have a pair of kidneys which is bean shaped. When the blood reaches the kidney it has both useful and harmful substance present in it. The kidneys absorb harmful substance from the blood. The waste is dissolved in water and is removed as urine. The urine from the kidney goes to the urinary bladder through tube like urethras. Urethra has an opening at end of the muscular tube through which urine passes out. The skin also helps in removing waste from our body in the form of sweat.

Lungs act as excretory organ by removing carbon dioxide (harmful gas) from the body.  

     A person has been put on dialysis. Which one of his following organs has failed to work?

(a)                        

(b)      

 (c)      

(d)   

(e) All of these  

Answer: (C)

       Which one of the following is a part of excretory system?

(a) Stomach

(b) Liver

(c) Heart

(d) Kidney

(e) All of these

Answer: (d)