Health and the Immune System This presentation is available online.

Disease Causing Organisms  Pathogens include infectious organisms from the kingdoms of Bacteria, Protists, and Fungi.  In addition, viruses, and other non-living pathogens cause disease.  Organisms from the Animal kingdom often serve as vectors for disease.  NOTE: Some diseases are genetic -- not infectious (they can’t be “caught”). We will learn about these later.

Prevention  Humans can avoid infectious disease with preventative measures: - Hand washing - Proper cooking of food - Treatment of water with inhibitors - Avoiding contact with pathogenic sources - Vaccines (more on this later)

Immune Response  Humans have also evolved physiological defenses against pathogens.  These defenses are part of our Immune System.  The Immune System includes both Non-Specific and Specific response systems.

Non-Specific Immune Response  Skin  Phlegm and secretions  Inflammation  Heat  Digestive enzymes

Specific Immune Response  Response to specific pathogens on a cellular level.  Attacks pathogens at specific sites called antigens.  Uses these “white blood cells”: - B Cells (type of lymphocyte) - T Cells (type of lymphocyte) - Macrophages  Much of the specific immune response happens outside the blood itself--wherever the infection is!

Specific Immune Response  B Cells: Humoral (body-fluid) Response: Mark and neutralize pathogens. Plasmas make Antibodies -- like bullets in a gun. Memory cells also. Watch this video: KRI KRI  T Cells: Cell Mediated Response Cells that destroy pathogens. Watch this video: MbA MbA  Macrophages: Work with both B Cells and T Cells to identify and destroy pathogens.

Specific Immune Response (Overview) “Eater cell”= Macrophage Some activated T cells (killer/ cytotoxic) also can find antigens and then destroy the invader. T cell

Treatment/Medicine  We also use medicine to fight disease!  Antibiotics kill living pathogens and include antibacterials and antifungals. These do not work on viruses (viruses are non-living).  Vaccines are dead or weakened pathogens used to stimulate the immune system’s production of antibodies. These are a preventative measure and our best present defense against viruses.