Whatever food we eat, passes through our gastric track filtered through the kidneys, and then eliminated from the bodies. The role of kidneys in our digestion is to filter out all the impurities and assure the secure absorption of the nutrients.
In this filtration process, there are severe chances that some hazardous impurities may stick up in the track and block or slow down the passage of urine. These hazardous materials can be small, rough slow down of mineral and acid salts. The thick ball is thus termed a kidney stone.
The term stone is given as the deposits are pure minerals and salts, which is the actual composition of a stone. A person suffering from a kidney stone may face mild to severe indications but the acuteness of the indications is what makes it a severe disease.