Introducing our immune system

One of my readers recently requested information about the human immune system. Imagine this scenario:  last weekend, you were planting white and pink vinca in your flower bed.  At one point you pulled off your gardening gloves; then before you put your gloves back on, you stabbed your finger on something sharp.  You immediately washed the dirt off your hands.  That night your finger started throbbing.  You noticed that finger was reddened, swollen, and hot when you touched it. 

What’s happening within your body?  When infectious agents (in this case, probably bacteria living in the dirt) enter your body, your immune system responds.  You might ask, how does my body know germs entered my finger?  There can be a period of time (called the incubation period) when the body does not yet recognize germs are inside and multiplying, gearing up to cause infection. But when the germs multiply enough to begin causing symptoms, our bodies recognize and begin responding:  the tiny blood vessels (arterioles, venules and capillaries) dilate and increase the blood flow to the area.  Fluid leaks out of the blood vessels into the tissues.  This causes swelling and heat in the tissues (two symptoms we would see and feel).  In the case of the infected finger, it would probably throb and hurt (another symptom we recognize.)   The infection-fighting white blood cells leave the blood vessels and begin their work of killing the germs. (I think of Pac-man chomping on those nasty germs.)  Our bodies produce chemicals which help kill the infectious agents (germs, virus, parasites, fungi) and boost the body’s inflammatory process to fight and cure the infection.  More information about our body’s response to infection can be found at http://textbookofbacteriology.net/innate.html

Thanks to modern-day medicine, treatment of this infected finger would probably get a cure.  Antibiotics might be enough.  In some cases, surgical opening (incision and draining) might be necessary to clean out and treat.  Oh, and don’t forget that tetanus booster shot because the tetanus germ can live in dirt. 

Have I got your attention now? I’ve given a very simple explanation of a truly complex, amazing response by the human body.  I’m going to be talking about our immune system for the next several posts.  It helps us fight off infections and more.  How does autoimmune disease and allergies fit into this topic?  I will explain.