Immune System Part II Physiology Standards: 10 a-e Once inside the body pathogens are met with several defense systems

The Immune System Nonspecific defenses continued If the skin is “broken” you will get what is called the inflammatory response Blood flow is increased as millions of white blood cells flood the infected area An elevated body temp. (fever ) is another form of defense creating a poor environment for pathogens A fever of 100 degrees F causes white blood cells to mature quicker while a fever of 103 or higher could cause some serious damage or even death

The Lymphatic System Your immunes system’s “pipeline” for transporting and housing specialized cells for fighting infections are found in your lymphatic system

The Immune System Specific Defenses of the Immune System When the body attacks foreign objects that have made it into your body it is called the immune response A substance that “triggers” an immune response is known as an antigen There are two types specialized cells that attack antigens B~ lymphocytes (B-cells)-produce proteins that inactivate pathogens that have not infected cells yet T~ lymphocytes (T-cells)-destroy body cells that are infected with pathogens

Antibodies Antigen binding sites Antigen Antibody B~ lymphocytes are responsible for making antibodies which are specialized proteins that are specifically designed to destroy specific pathogens by recognizing antigen binding sites

Antibodies Antibodies are proteins that recognize and “bind” to antigens Once the infection is destroyed, memory B-cells remain capable of producing that specific antibody in case you receive the same infection It is estimated that a healthy adult has around 100 million different types of antibodies to fight infection The more “exposure”, the more antibodies you create in your “library”

B Cells & Humoral Immunity Antibodies “clump” the antigens and phagocytes “eat” the pathogen clumps Surface proteins on antigens trigger memory B Cell production Activated B cells release millions of antibodies

T Cells – “Pathogen Destroyers” Once an antigen or infected cell is in the body T Cells use their surface proteins to recognize the antigen and start making more T Cells Activated T Cells remain in the body forever waiting for a future invasion T Cells use many methods to “kill” the antigen or infected cell directly

Acquired Immunity Humans have long wanted to prepare people before they become infected with a disease, especially when the disease could potentially kill them A vaccination can be a: A weakened form of the original pathogen A “killed” pathogen that still has it’s shape for the immune response An alternate form of the disease such as cowpox to trigger the immune response for smallpox

Acquired Immunity Two Types of Immunity: Antigens in a vaccine trigger the immune response and Memory B Cells are made Two Types of Immunity: Active Immunity – the type of immunity that is generated by the body following exposure to a pathogen or after a vaccination Passive Immunity – can be utilized by injecting antibodies to the infection that were created by another animal

Diseases that Weaken the Immune System Your immune system is your internal defense system against all infections and pathogens, right? What happens if a pathogen attacks your Immune System? Leukemia is cancer of the bone marrow Leukemia weakens bones and makes them unable to produce disease fighting white blood cells HIV (Human Immunodeficiency Virus) is another

HIV kills T-Cells until the host’s immune system is so weak that the host is unable to fight off mild infections HIV HIV enters the body through direct contact and sharing of blood or fluids