Immune system

Immune System A system that prevents disease and infection What is our immune system? A system that prevents disease and infection The immune system “cleans the body” by removing what? Pathogens such as bacteria and viruses

1st Line of Defense Three things that are included in in our first line of defense include: 1. SKIN (acts as a barrier) 2. Mucus/Cilia Mucus = sticky to trap germs Cilia = tiny hairs that “sweep” out germs 3. Gastric Juice (acids in stomach kill germs)

2nd Line of Defense 1. Inflammation (phagocytic WBC’s) 2. FEVER Two things that make up the 2nd line of defense are 1. Inflammation (phagocytic WBC’s) 2. FEVER When do we need the 2nd line of defense? When the 1st line fails and pathogens get into the body!!

INFLAMMATION 1. What is Inflammation? an increased blood flow to a part of the body that has been injured or invaded by a pathogen (hot, red, swollen) 2. Why do you think the skin over an infection is hotter than the surrounding skin? There is more blood at that site so it raises the temperature 3. What line of defense is inflammation? 2nd line

3rd line of defense What is your body’s 3rd line of defense? Anti-bodies What are anti-bodies? Specific proteins that are made by WBCs to fight off pathogens Where would we find anti-bodies? Plasma of the blood What is an antigen? Anything that can stimulate an immune response

Shape What is the most common shape of an anti-body? The “Y” shape How does the shape of an antibody change from a T to a Y? When it connects to an antigen Do you think antibodies are shape-specific? That is, do the antigen and anti-body have to fit together properly for it to work? YES

Lymphocytes-A special type of WBC that makes antibodies What is another name for WBCs? Leukocytes What does the word “phagocytosis” mean? Cell eating

New Invaders What does it mean when we say antibodies are specific? Their shape has to fit with the antigen they are fighting Do you think this is a specific defense? YES! What happens when a pathogen invades the body? Anti-bodies are created