Your body contains 5,000 to 10,000 white blood cells in each cubic millimeter of blood. These, unlike the red cells, are independently mobile. They can move to where they are needed, either in the bloodstream or outside it. Simply stated, their crucial job is defense. Yes, they are constantly saving your life.
You have various types of white blood cells. Two of them, your granulocytes and monocytes, serve as ever-vigilant "policemen" within you. By accident you might scratch your arm, letting dangerous bacteria into your body. Immediately these "policemen" are alerted. They are able to pass through the walls of your capillaries and engulf invading bacteria, digesting them with potent enzymes. The pus that forms at the site of an infection tells you that they are on the job, for it consists mainly of white cells and defeated bacteria. White cells also respond if you have an infection inside your body, such as appendicitis. In fact, one way your doctor can confirm the seriousness of such diseases is by checking your white-blood-cell count. If it is elevated, it indicates that your white cells are rallying to fight an acute infection.
You have various types of white blood cells. Two of them, your granulocytes and monocytes, serve as ever-vigilant "policemen" within you. By accident you might scratch your arm, letting dangerous bacteria into your body. Immediately these "policemen" are alerted. They are able to pass through the walls of your capillaries and engulf invading bacteria, digesting them with potent enzymes. The pus that forms at the site of an infection tells you that they are on the job, for it consists mainly of white cells and defeated bacteria. White cells also respond if you have an infection inside your body, such as appendicitis. In fact, one way your doctor can confirm the seriousness of such diseases is by checking your white-blood-cell count. If it is elevated, it indicates that your white cells are rallying to fight an acute infection.