Human beings live with and are surrounded by billions of bacteria and viruses. Some are good and help our bodies, but some make us sick. Lucky for us — and not so lucky for the bad bugs — getting into the human body is not easy. These bug invaders will try to get through in many ways: through the skin, nose, mouth, ears or eyes.
Thankfully the body’s immune system has incredible defense mechanisms designed to keep the invaders out: the skin is thick and hard to penetrate; the nose has cilia (little tiny hairs) and goopy mucus that trap dirt and bugs; the eyes have tears that wash them away; and the mouth produces saliva and other chemicals the bugs do not like.
These are the immune system’s first line of defense. Occasionally, bug invaders do break through this line of defense and enter the body, and when that happens the body works in even more amazing ways to protect itself.
The brain sends an alert signal out to the immune system. This signal triggers inflammation, which causes the blood vessels to dilate and increase blood flow. When this happens, a team of white blood cells, or leukocytes, flocks to the scene of the crime.
There are many types of white blood cells, including macrophages, lymphocytes, basophils, neutrophils, and eosinophils. The different white blood cells all have different jobs and come from different areas in the body such as the thymus, spleen, or bone marrow. They can travel through the blood but usually travel through a special system designed just for them, called the lymphatic system.
Once at the invasion site, the white blood cells get to work doing their special jobs. The macrophages will eat up the invaders, and the lymphocytes will not only help destroy the invaders but will remember and recognize them, in case a similar bug comes in for a future attack. White blood cells are like little warriors floating around in your blood waiting to protect you from any virus or bacteria enemies.
To help the immune system stay strong and healthy, it is very important to eat healthy, balanced meals full of colorful fruits and vegetables, and not too much sugar. The invaders love sugar as it makes them grow stronger and even multiply. It is also essential to get plenty of sleep, have fun, laugh a lot, and be happy!
For children to learn more about the immune system, Dr. Heather has created an elementary curriculum that follows her award winning story in the human Body Detectives series, The Lucky Escape. To bring the curriculum into your child’s school visit the Human Body Detectives website.