Activity 2: Bacteria vs. the Immune System

Entering the body Bacteria naturally live in your body. These bacteria usually are not harmful, instead they help your body in a number of bodily processes such as digestion. Harmful bacteria, also known as pathogens, enter your body through: Cuts or scraps The mouth due to food/water that you consume or putting unclean hands near/in/on your mouth

White blood cells When bacteria are inside your cells, the body’s main defense are white blood cells. There are two types of white blood cells that help in fighting off pathogens such as bacteria Phagocytes Lymphocytes These white blood cells perform two different mechanisms in order to destroy the bacteria once they enter the body.

Mechanism 1:Phagocytes Phagocytes are white blood cells who engulf bacteria that enter the body. How? When bacteria enter the body, they release chemicals out into the cells. These chemicals are recognized by the phagocytes. Once a phagocyte recognizes these chemicals, these white blood cells engulf the bacteria. Once engulfed, the bacteria are broken down inside the phagocytes

Mechanism 2: Production of Antibodies Lymphocytes are white blood cells that produce antibodies in response to bacteria that invade the cell. The lymphocytes are prompted to release these antibodies when they are alerted to certain antigens on the outside of the bacteria The antibodies recognize SPECIFIC antigens.

Once the body makes antibodies for a specific bacteria, each time that same bacteria enters the body those same antibodies will be produced to fight off the infection. The immune system develops a “memory” for bacteria that has already entered the body.

Finish Early? Provide an example of a structure in a city that would be similar to a bacterium in the body. Explain how that structure is similar to a bacterium.