Immune System and Stress
How quickly a deceased human (or animal) body breaks down is testament to how well the immune system works. While a body is alive, the immune system protects the body at every living moment from bacteria and other foreign invaders. The immune system is a complex system of cells -- which have varying functions -- and generated at discreet regions of the body, a circulatory system -- the lymphatic system -- that feeds of and into the blood circulatory system and lymph nodes that act as effective filters and stores of foreign bodies marked for destruction by antibody action. Most of the time, the immune system protects the body. But on rare occasions we might need outside help: this is when he system does not "figure out" the invasion and the body has to be coaxed into producing antibodies by inoculation with weaker forms of the pathogen. In the case of HIV and AIDS, the body has not been able to create an effective defense, thus these immune deficiency disorders have become the scourge of the last few decades. This essay will not only describe key component of the immune system and how a body uses this system, but will also explore the cause and effect relationship between stress, the immune system and certain diseases.
Key Components of the Immune System
While elaborating on the immune lymph system, one often fails to recognize the role of the skin and openings on the face as the first line of defense. The outer epidermis protects the entire body. The epidermis contains Langerhans cells mixed with melanocytes. These cells warn the immune system of impending attacks. The skin also has antibacterial properties. Nasal passages contain tiny hair that trigger sneezing mechanism to expel germs. The mucus also serves to trap bacteria. The eyes are also exposed. Tears and mucus contains lysozyme, which digests the cell walls of certain bacteria. The basic internal defense mechanism is associated with the lymphatic system. Lymph is a plasma component of the blood that flows (without heart pressure) through the body. Lymph receives nutrients from the blood and carries it to the cells. This fluid also detects the presence of pathogens and signals the defense mechanism. This plasma is filtered through the lymph nodes back into the blood stream. Lymph nodes are found at strategic regions in the body: in the adenoids, tonsils, armpits, groin and in the Peyer patches in the lower abdominal region. These nodes contain cells and tissue. They trap bacteria and other foreign objects. Swollen lymph nodes are a sign of infection. (Brain, 2003)
Three organs are important in the immune system. The thymus, which is situated between the breastbone and the heart, the spleen and the bone marrow are responsible for producing the different types of cells that are responsible for defense. Specific immune cells produce antibodies (antibody mechanism discussed in the next section) by the immune cells in response to an antigenic (foreign body) attack. These are often called immunoglobulins (Igs) and gammaglobulins. Antibodies are proteins that bind to toxins and antigens disabling the function of these invaders or signal action from other cells. Antibodies work in collusion with Complement proteins, a set of free-floating proteins in the system. The liver produces this set of nine proteins. The immune system also contains several hormones called lymphokines. For instance, tymosine signals the production of lymphocytes. Interleukins (IL) are produced by white blood cells. IL-2 suppression in AIDS patients has come under a lot of scrutiny in developing treatment modalities for that disease. (Yarchoan, Mitsuya and Broder, 1993) TNF or tumor necrosis factor kills tumor cells. Interferon targets viruses.
The cells primarily implicated in a body's defense mechanism are white blood cells. Depending on their function, WBCs or leukocytes are of different types, all produced in the bone marrow. The different types are Granulocytes (further subdivided into neutrophils, eosinophils and basophils), lymphocytes and monocytes. The last and the largest enter the tissues and are then called macrophages. These cells "swallow" up the detritus of infections such as whole bacteria, dead cells and tissues. Lymphocytes are further divided into B cells and T cells -- these are critical to the immune system. B cells produce antibodies that create marks on antigens. This signals that these entities should be destroyed. B cells circulate in the blood and the lymph. T cells coordinate and regulate the overall immune response. They not only mark the antigens (helper T cells), but they can also destroy diseased cells. There are certain cell molecules called MHCs (major histocompatibility complex). These...
Our semester plans gives you unlimited, unrestricted access to our entire library of resources —writing tools, guides, example essays, tutorials, class notes, and more.
Get Started Now