Anatomy & Physiology II
May 9, 2012
The Human Immune System
The human immune system is a complex protection mechanism designed to protect the body from millions of viruses, bacteria, microbes, parasites and toxins that would invade the body. The immune system is complex, intricate and designed to maintain a defense against harmful invaders into the body.
Some of the more common invaders to the human body are bacteria and viruses. When a virus or bacteria invades your body and reproduces, it causes infections. Their presence produces some side effect that makes you ill. An example of which is the strep throat bacteria (Streptococcus). This bacterium releases a toxin that causes inflammation in your throat. Viral and bacterial infections are by far the most common causes of illness for most people. They can cause illnesses such as colds, influenza, measles, mumps, malaria, AIDS and so on. The job of your immune system is to protect your body from these infections. The immune system protects you in three different ways:
1. It creates a barrier that prevents bacteria and viruses from entering your body. 2. If a bacteria or virus does get into the body, the immune system tries to detect and eliminate it before it can make itself at home and reproduce. 3. If the virus or bacteria is able to reproduce and start causing problems, your immune system is in charge of eliminating it. There are several components to the immune system. The most obvious part of the immune system is the skin or epidermis. The skin acts as a primary boundary between infection and your body. Part of the skin's job is to act as a barrier. Skin is generally impermeable to bacteria and viruses. The skin contains special cells called Langerhans cells that are an important early -warning component in the immune system. The skin also secretes antibacterial substances. Most bacteria and spores that land on the skin die quickly. The nose, mouth...
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