Period 3 Ethan T, Joshua G, Sydney E, Bryan E Immune System Period 3 Ethan T, Joshua G, Sydney E, Bryan E

Main function The main function of the immune system is to fight off infection and pathogens that enter the body. Your skin is the first line of defense as part of the innate immune system. In our bloodstream there are a number of types of white blood cells that destroy foreign invaders as part of either the innate immune system or the acquired immune system.

Innate vs Acquired Immunity Innate immunity- Functions as soon as a foreign entity enters the body. Phagocytes, mucous membranes, and skin all function to destroy or prevent infections from pathogens as soon as they enter the body. Acquired immunity- The part of the immune system that fights off localized infections that the innate system cannot destroy completely. T cells and B cells recognize and destroy specific pathogens, and remember certain infections for a lifetime. Vaccinations teach the acquired immune system.

Vaccines A vaccine is a biological injection designed to provide acquired immunity against viruses. They contain weakened or dead microbes and viruses, so that the body’s immune system can recognize and destroy the intruders in the case of a real future infection. Though vaccines have garnered controversy over health concerns, vaccines are generally accepted as a safe method of immunization with only rare adverse effects.

Cell types A phagocyte is a cell that destroys pathogens by surrounding and engulfing them. T cells destroy body cells that are infected with pathogens. B cells produce proteins that inactivate pathogens that have not yet infected a body cell.

Proteins Antibodies are proteins made by B cells. Antibody Antibodies are proteins made by B cells. Antibodes can 1) bind to the surface of a pathogen, preventing it from entering a cell, 2) complement other immune proteins (sometimes called complement proteins) to destroy the pathogens, or 3) mark the pathogen for destruction by a white blood cell. Interferons are proteins produced by body cells that are infected by a virus. The infected cells release interferons, which stimulate uninfected body cells to produce enzymes that will prevent viruses from entering and infecting them. A 3D model of a human interferon protein

Organs in the Immune System Tonsils- Trap pathogens on the surface of the tonsils so T cells and B cells can attack Lymph nodes- Contain and circulate lymphocytes

Organs in the Immune System Bone Marrow- Produces red blood cells and lymphocytes that are part of the lymph system. Thymus- The thymus is located beneath the sternum and is a specialized organ that is only active when a person is young. Believed to be helpful when a person is still developing an immune system. Skin- First line of defense, keeps out any pathogens or viruses that would otherwise easily enter the body without the protection of skin.

Homeostasis Homeostasis is the maintenance of a stable equilibrium between internal processes and elements. The immune system aids in homeostasis by combating pathogens within the system so as to prevent disruption of the body’s normal function.

Relation with Other Systems The immune system works closely with the circulatory system by transporting white blood cells. The digestive system works with the immune system to decipher which foreign objects are food or pathogen. The lymph system helps regulate immune response to a virus by controlling body fluids.

Diseases that affect this system Acquired immunodeficiency syndrome (AIDS), caused by the human immunodeficiency virus (HIV) Type 1 Diabetes Rheumatoid Arthritis Lupus

HIV/AIDS HIV attacks the T Helper immune cells (CD4+ T cells) T cells, that would normally regulate immune function, can no longer perform this task With the body unable to recognize pathogenic threats, the immune system is compromised, and infections become unfightable This is called Acquired Immunodeficiency Syndrome

Type 1 Diabetes It is believed that the primary cause of type 1 diabetes is that the immune cells attack healthy body tissue The cells in the pancreas which create insulin are broken down by white blood cells Blood sugar cannot be processed because of the lack of insulin The result of the disease is that blood sugar can reach harmful concentrations if left unchecked or without treatment