Understanding the Immune System

Study Notes

Immune System Function

The human body's primary defense against disease is its immune system. This complex network of cells, tissues, organs, and proteins work together to protect us from pathogens like bacteria and viruses. The main components of this system are white blood cells, which fight off infection and help repair damage caused by illnesses; antibodies, which recognize foreign invaders; and complement proteins, which destroy bacteria and other pathogens. Additionally, there are specialized cell types including lymphocytes such as T-cells and B-cells that play important roles in fighting off microbes.

Immunodeficiency Disorders

Some people have weakened immune systems because they lack certain genes needed to make parts of their immune system work properly. These conditions are called primary immunodeficiencies. Some examples include:

Severe combined immunodeficiency (SCID): A rare disorder where children can get very sick after being born with it. They may get many different kinds of infections over time.
X-linked agammaglobulinemia (XLA), also known as Bruton’s syndrome. It affects males more often than females. People with this condition don't produce enough spaces within their white blood cells so they cannot activate them when necessary.
Wiskott-Aldrich Syndrome (WAS) which mostly affects boys who develop serious bacterial infections early in life.

Primary immunodeficiencies typically affect only one part of the immune system while secondary immunodeficiencies weaken the whole system. Examples of these include malnutrition, HIV/AIDS, cancer chemotherapy treatments, drugs, radiation therapy, and some hereditary genetic defects.

Autoimmune Diseases

Autoimmune diseases occur when your own immune system mistakenly attacks healthy tissue. Common examples of autoimmune diseases include rheumatoid arthritis, type I diabetes, multiple sclerosis, Graves' disease, Hashimoto thyroiditis, psoriasis, and celiac disease. An estimated 2% of Americans live with one form or another of an autoimmune disease - most commonly women between the ages of 30 and 60.

Vaccines & Immunizations

Vaccinations involve giving small amounts of non-infectious material related to a specific virus or bacterium into a person's bloodstream. When a vaccine is administered to someone, his or her immune system responds by making defenses against the agent. Then if he or she encounters the real infectious substance later on, the immune system recognizes it and fights back again without getting the person really sick. Because of this process, vaccinated individuals do not usually become ill after exposure to the microorganisms contained in the vaccination. In addition, vaccinations can prevent the spread of particular diseases among large groups of people.

Immune Response to Infection

When our bodies detect bacteria or viruses entering through our skin pores or mouth, respiratory tracts, or digestive systems, the immune system kicks into action. Cells involved in this response release chemicals to attract additional immune cells to the area under attack. Eventually, the infection is cleared away, leaving behind memory cells ready to respond faster next time. Without an effective immune response, an organism could easily catch every cold or flu going around in its community.

Description

Explore the functions of the immune system, including how it protects the body from pathogens, the role of white blood cells, antibodies, and complement proteins, and the importance of lymphocytes like T-cells and B-cells. Learn about immunodeficiency disorders, autoimmune diseases, vaccines, and how the immune system responds to infections.