body systems

immune system

What is immune system? Immune system is the defense system of the body. Namely immune system is the body's ability to fight against  diseases. Immunity may be inherent or acquired.  Naturally each person f...

digestive system

When you think about something tasty, digestive system begins to release more saliva than  normal levels. It is common to say: "It makes my mouth water”. This formation of saliva is just the first step of diges...