A healthy human body is a capable of some extraordinary feats. It can maintain a continual heartbeat throughout life. It has lungs that breath without prompting. It has an amazingly complicated brain that allows for the most basic functioning, while having the potential to create breathtaking pieces of art, dissect the most complex scientific principles and imagine the unimaginable. One of the most astounding aspects of the human body is its ability to protect itself. Through a dynamic system of mechanisms, the body can defend itself against disease and illness by recognizing and destroying pathogens, viruses and toxins that invade the body. This structure of protection is called the immune system, and it works every day to keep the body healthy and functioning.
The immune system contains a network of proteins, tissues, organs and cells that work together to defend and attack organism and other invaders, called antigens, that can harm the body. The cells involved in the immune system are called leukocytes, or white blood cells. There are two types of leukocytes, phagocytes and lymphocytes, and each has a distinct role in the immune process. The phagocytes are the cells that ingest harmful substances in the body, like dead cells, bacteria or toxins. Lymphocytes, which are either T cells or B cells, are a vital part of immune functioning as they recognize any previous contact with invading antigens. B cells create antibodies, proteins that latch onto specific antigens, neutralize the antigens, while T cells destroy them. Lymphocytes have the ability to adapt to changes in the structure of these harmful invaders.
Originating in the lymphoid organs, which include the spleen, bone marrow and the thymus, leukocytes travel along the lymphatic vessels between the organs and the lymph nodes, where they are stored, as well as through the blood. When an antigen attacks the body, the body begins its immune response. The immune system works together to recognize the antigen in order for the B cell lymphocytes to produce antibodies to lock on to the antigen. If the body has already encountered and destroyed an antigen, the B cell has antibodies stored and ready to attack it. These stored “remembered” antibodies are why vaccinations are effective. However, if the antigen is new, the B cell produces a new antibody. Once the antibody from the B cell has latched onto the antigen, it is neutralized, and the T cell then moves in to destroy it. The T cell also triggers the phagocytes to ingest any harmful toxins or bacteria that are involved in the attack. This immune response is in what keep the body healthy and free from disease.
The immune system is crucial for fighting off bacterial and viral infections. Bacteria, living organisms sometimes referred to as germs, reproduce in the body, causing bacterial infections. The illness and its effects depend on the type of bacteria. When food infected with bacteria, such as salmonella, has been ingested, it multiplies, causing illness, in this case salmonellosis. The body’s reaction to salmonella is stomach pains, nausea, diarrhea, chills, headache and vomiting. In the case of strep throat, streptococcus bacteria release toxins that cause an inflamed throat. If the bacteria cannot be destroyed by the immune system, they can be countered with the help of antibiotics. Viral infections, on the other hand, are powerful, but different than living bacteria. They need living hosts to survive, and they alter the cells and reproduce quickly. Antibiotics are not effective for most viral infections. For viral infections, such as influenza, hepatitis B and C, influenza, and HIV, there are antiviral drugs that can weaken a virus. In the body, the T cell lymphocytes can destroy some viruses. When an immune system is not working properly, even medical science has difficulty staving off viral infections.
Although the inner workings of the immune system are a vital part of the body’s defense, there are other parts that play a role in keeping a body healthy. The skin, or epidermis, not only acts as a barrier to keep out harmful elements, it also produces an antibacterial matter that destroys many of the germs and mold spores that land on the body. In addition to the skin, tears, mucus and phlegm contain antiseptic enzymes that destroy many forms of bacteria. This is especially critical for guarding the parts of the body that provide easy access to bacteria, such as the throat, lungs and nasal passages.
The immune system plays an important role in keeping the body healthy and free from illness. As a first line of defense, the epidermis, provide a barrier to keep bacteria and viruses out. The leukocytes, the B and T cell lymphocytes and the phagocytes work to identify harmful bacteria and viruses before they can reproduce. If reproduction begins, immune system works hard to destroy the invaders. A healthy human body is an intricate machine with all its parts working together for optimal functioning. The immune system plays its role as a defender against the many harmful elements that can cause damage to the extraordinarily complex human body.