The human immune system is very complex, and the body’s largest organ, the skin, provides the first order of defense when a virus, bacteria or some other pathogen tries to get into the body.
The skin, which is multi-layered, provides a natural barrier to pathogens lurking outside of us. The outermost layer of skin is called the epidermis, the next layer the dermis, and below that is the subcutaneous fat layer. These layers provide a substantial barrier of protection from pathogens which we come in contact with on a daily basis.
However, as we all know, pathogens still make their way into our body anyway. Whether it be through a cut or injury to the skin, or something we inhale or ingest, we still get sick occasionally. What most people probably don’t realize is just how efficient our immune system is, and how much it protects us.
Once inside our bodies, there are several ways that our immune system fights off illness. One of the simplest ways is by the act of sneezing and coughing. Sneezing and coughing can be an effective way to remove pathogens and other types of irritants from the respiratory system. Other bacteria and viruses can be dispelled from the body through urine; and many bad organisms can be neutralized by stomach acid.
More complex immunity is found through something called antibody production. Antibodies are proteins which are formed in response to a foreign substance (antigen) which has gotten into the body. The antibodies produced in response to the bacteria or viruses are able to neutralize these organisms and often times prevent illness. Antibodies are produced by white blood cells (the B lymphocyte), cells which our bodies make. For these white blood cells to fight off disease however they must be present in sufficient amounts; so if another type of disease or disorder is present in someone, it would be more difficult for the person to fight off a secondary infection.
Another type of white blood cell involved in human immunity is the T lymph cell. Like the B cell, the T cell has a receptor site which can be specific for targeting a particular pathogen. T cells include: T killer cells, cells that specifically kill viruses and other pathogens, and T helper cells, cells which actually aid in the immune response. T helper cells are able to help determine what type of help the body needs.
Both killer T cells and helper cells help to identify such things as tumors growing inside our bodies. The mechanism for this is complex, and there are still tumors which escape the immune system and become cancerous.
The human immune system is extremely complex. This is just a general overview of immunity and how the body can help fight disease. Hopefully, this overview gives the reader a little insight into a very important, but highly complex system that is so important to the body.