Immune System Body's line of defenses

What are nonspecific defenses? Skin Mucus membranes Inflammatory response

Skin first line of Nonspecific defense Acts as a barrier Chemical defenses (sweat, oils, waxes)

Mucus membranes first lines of Nonspecific defense Mucus traps pathogens

Inflammatory Response Second line of defense Nonspecific immunity Suppress infection and speed recovery 1. Release histamine 2. Raise body temperature 3. Phagocytes leak out of capillary and attack 4. Phagocytes destroy pathogen

White blood cells (lymphocytes) Phagocyte -- “eater of cells” Neutrophil -- ingest pathogens Macrophage -- stationed in body tissues engulf large pieces of debris and display antigens. Natural killer cells -- attack infected cells or cancer cells (cytotoxic T cells)

More White Blood cells Helper T cells B cells Plasma cells Memory cells

Fever

Proteins Interferon released by virus infected cells causes nearby cells to resist virus infection

Specific defense Immune Response

Immune Response Primary-1 st time exposed to pathogen Secondary-2 nd time exposed much faster because memory cells immediately respond and produce antibodies to destroy.

Vaccination Put antigens in the body that fool the immune system into reacting like the real pathogen was there.

Pathogens Any disease causing agent Examples: Bacteria or Viruses

Immune response differences Bacteria are single celled organisms that reproduce by mitosis (binary fission) Bacteria are prokaryotes If you get a bacterial infection that your own immune system cannot stop then a Doctor can prescribe Antibiotics.

Immune response differences Viruses are not considered living because they are not made of cells. Viruses use the cells they attack in order to make copies of themselves. Some viruses contain DNA other viruses contain only RNA. We cannot cure a virus infection We can get vaccinations to help try prevent virus infections