Immune System Defenses

Day 3

Immune System Defenses

 

Lesson Objectives

• Describe the immune system.
• Explain how lymphocytes respond to pathogens.
• Define immunity and vaccination.

If pathogens get through the body's first two lines of defense, a third line of defenses takes over. This third line of defense involves the immune system. It is called the immune response. The immune system has a response for each type of pathogen.

The lymph organs are the red bone marrow, thymus, gland, spleen and tonsils(which I had to get removed a few years ago). Each organ has a different job in the immune system:

Red Bone Marrow is found inside many bones, including the femur. Red Bone Marrow makes lymphocytes.

  

The Thymus Gland is in the chest behind the breast bone. It stores lymphocytes while they grow older.

The Spleen is in the abdomen below the lungs. Its job is to filtered out of the blood are destroyed by lymphocytes in the spleen.

The Tonsils are in the throat. They trap pathogens that enter the body through the mouth or nose. Lymphocytes in the tonsils destroy the trapped pathogens.