Guiding Questions How does your body keep invading pathogens out? How does your body fight off pathogens that have invaded? What does it mean to be ‘immune’ to a pathogen? What can you do to prevent from contracting a pathogen (from getting sick)? What is the relationship between cold weather and becoming sick?

Objective 5 – Your immune system transmission hypothalamus T-cells B-cells host antibodies pathogen white blood cells leukocytes immune fecal antigen om/health-and- medicine/bubonic- plague-outbreak- spreads-madagascar

Your defenses against disease or pathogens What are your body’s 3 lines of defense against invaders? What are your body’s 3 lines of defense against invaders? Describe the parts of the first 2 defenses. Describe the parts of the first 2 defenses. zsEMghttp:// zsEMg (lines of defense) zsEMg

Immune system cells Made of white blood cells (WBC’s) Also called leukocytes WBC‘s are made in your bone marrow Antigen = pathogen

Immune system: Macrophages Macrophages are white blood cells that patrol your system When they detect pathogens they ingest (eat) them ure=relatedhttp:// ure=related (real) ure=related

A call for help When the macrophages are overrun the macrophages call for the Helper T-cells Helper t-cells are like the commanders – they do not fight but they call for the B-cells

B-cells Produce a specific antibody (target) for one specific of antigen (pathogen) and makes this antigen a target. The antibodies either –kill the pathogens –or make them a target for macrophages or Killer-T cells

Killer and suppressor t-cells The Helper T-cells also call in the Killer t-cells. The killer T-cells find the antigens that were marked by the B-cells and destroy them. Suppressor t-cells give your immune system the all clear sign and close down the Killer T’s

Memory t-cells (green) WBCs that record how to identify pathogens. This will allow your immune system to act quickly if they see the same microbe or virus again.

Research and Videos A study conducted by Dr. Davidson at the University of Wisconsin has demonstrated that negative emotions can lead to a weaker immune system (Goode, 2003) relatedhttp:// related (awesome!!) related

Summary Macrophages patrol and ingest antigens (pathogens) When overrun the macrophages call the Helper T- cells The helper T-cells call in the B-cells The B-cells make antibodies to shoot at the antigens: antibodies kill or mark the antigens The Helper T-cells call in the Killer T-cells if the B- cells need help Marked antigens are destroyed by Killer T-cells or macrophages When the pathogen is contained, the suppressor cells stand down the Killer T-cells The memory T-cells remember the specific antigen

Resources Goode, Erica. "Power of Positive Thinking May Have a Health Benefit, Study Says." Power of Positive Thinking May Have a Health Benefit, Study Says. New York Times, 3 Sept Web. 10 Nov (longer) Cartoon-Story.php Cartoon-Story.php munesystemdo/howdoesyourimmunesystemwork.aspx munesystemdo/howdoesyourimmunesystemwork.aspx (3D animation) (3D animation)