Then importance of the cells. What role do they play within us?... Let's see...

Each of us is the result of a handful of tiny stem cells that multiplied to produce the 200 types of specialized cells in our body.

Our stem cells continue to be active to keep us healthy -- without them, we wouldn’t survive more than a few days! The exhibition We are surrounded by millions of bacteria, viruses and other microbes (germs) that have the potential to enter our bodies and cause harm. The immune system is the body's defense against pathogens (disease-causing microbes). The immune system is made up of non-specialised defences such as skin and the acidic juice produced by your stomach. But it also has some highly specialized defences which give you immunity against (resistance to) particular pathogens. These defences are special white blood cells called lymphocytes. Other types of white blood cells play an important part in defending your body against infection.

 The immune system is generally divided into two parts. The first part is the defences you are born with. These form what are known as the innate system.

The second part of your immune system, known as immunity, develops as you grow. Your immunity gives you protection against specific pathogens. Not only can this system recognize particular pathogens, it also has a memory of this. This means that if you encounter a certain pathogen twice, your immune system recognizes it the second time around. This usually means your body responds quicker to fight off the infection.

 The innate system is found in many different places around the body. First line of defense is your skin. Skin forms a waterproof barrier that prevents pathogens from entering the body. Your body cavities, such as the nose and mouth, are lined with mucous membranes. Mucous membranes produce sticky mucus which can trap bacteria and other pathogens. Other fluids produced by the body help to protect your internal layers from invasion by pathogens. Gastric juice produced by the stomach has high acidity which helps to kill off many of the bacteria in food. Saliva washes pathogens off your teeth and helps to reduce the amount of bacteria and other pathogens in your mouth.