The Immune System Anatomy and Physiology

Immune System Your body’s protection against pathogens (disease causing agents) Two major categories of defense: Non-specific and specific

Immune System Non-specific defenses are general, and will work against any pathogen Species resistance, mechanical barriers, chemical barriers, inflammation, phagocytosis

Immune System Specific defenses fight off only one particular pathogen Lymphocytes specialize and become T cells and B cells T cells activate B cells B-cell Activation B cells produce antibodies; the single most effective protection

Antibody structure Y shaped Variable part fits only one antigen Very specific

Antibodies on B cells

Immune System Antibodies are made in response to a specific antigen Takes a while to figure out the exact shape to fit the antigen Once made, memory cells will be kept for future exposures

Immune System Memory cells explain why you don’t get the same disease twice Some common illnesses, such as cold and flu, are really different mutated forms of the virus. Each time takes a different antibody

Immune System Vaccines: are killed or weakened antigens They cause you to make the antibodies and memory cells without you getting sick They are ready if you are ever exposed

Type of Immunity Active: You make the antibodies in response to an antigen Passive: Already made antibodies are given to you—mother to baby; some injections for illness

Type of Immunity Naturally acquired: you came across the pathogen naturally (got sick) Artificially acquired: a vaccine; you stimulate the exposure on purpose

Type of Immunity Naturally acquired active immunity Naturally acquired passive immunity Artificially acquired active immunity Artificially acquired passive immunity (does not last long) Primary: first exposure (get sick, takes time to make antibodies) Secondary: 2 nd or more exposure (quick response from memory cells)

What vaccines have you had? Hepatitis B DPT Polio MMR Hib Pneumococcal