One of the more intriguing functions of the body is the immune system. This bodily system is designed to fight any diseases which might attack any part of the body. In this article, we will give a basic overview of the immune system, discuss how it works and why it has an impact on the origins debate.
Before I go any further, I should point out that the Immune System is far more complex than any one article could possibly cover. Whole books could be written about about the Immune System and just barely scratch the surface. For the purposes of this article, we will simply skim the surface, but keep in mind that the actual process is far more complex than what I describe. That said, let us have a look at the Immune System.
The Immune System, as the name implies, is a system rather than an individual entity. Immune systems are found in countless creatures through out the world. However, the human immune system is what we will focus on today. The immune system is composed of many different parts, the vast majority of which are microscopic. It can be broken down into the Innate Immune System and the Adaptive Immune System.
The Innate Immune System is not typically what we think of when we think about fighting diseases. For example, the innate immune system contains the skin, which helps keep most pathogens out of the internal organs. The role of the innate immune system is largely preventive, though there are some actual disease fighting components. The skin and cellular barricades such as cell membranes are designed to keep the vast majority of of pathogens, such as bacteria, and viruses, out of the body. However, the innate immune system is also responsible for inflammation, which draws oxygen rich blood to the site of an infection and helps the body defeat a potential pathogen. As an augment to this, the innate immune system uses something called “Natural Killer Cells”. Natural Killer Cells work in a unique fashion. Every cell in the body has a specialized marker on it that tells the rest of the body that it is “self”. Natural Killer Cells are pre-programmed to detect those special markers. If they detect a cell which does not have the specialized “self” marker, they will attack and kill the cell if they can.
The Innate Immune System is useful and does excellent work, but the Adaptive Immune System takes the immune system functions several steps further. It features cells called Lymphocytes. Lymphocytes are divided into two types, the B cells and the T cells. Each one has separate, distinct functions. In the following paragraphs, we will discuss what each one of them does.
B cells are perhaps the slightly less complex of the two so we will begin with them. B cells have a couple of functions. Every cell has special identifying markers on it, called antigens. These special antigens are the basis of B cell function. B cells produce specialized substances called antibodies, which react to specific antigens. These antibodies are designed to attach to specific antigens. The antibodies produced by B cells are meant to begin an immune response against a pathogen. When a B cell spots a foreign cell, it attempts to bind to it. Once it has bound itself to the pathogenic cell, the B cell begins to produce antibodies. These antibodies are used to kill off disease carrying cells.
T cells come in two varieties, Helper-T cells and Killer-T cells. Killer-T cells function exactly as might be expected based on their name. They are designed to kill cells infected with any kind of disease or virus. They function differently than B cells in that they do not produce antibodies. Instead, they rely on specialized chemical recognition to pick out antigens which are foreign to the body. Once they are recognized, the Killer-T cell attacks and kills the infected cells. Helper-T cells, by contrast, do not have any killing power. Instead they function as traffic directors of sorts. When they encounter a foreign cell, they immediately send out the word throughout the area and Killer-T cells come to the spot and attack the intruder.
Due to the complexity of the Immune System, I have been forced to break this article into multiple parts. In part two, to follow in an upcoming post, I will dive a little deeper into how the immune system works.