Friday, November 29, 2013
The Immune System and Germs
Today we started a new part in our Science unit of cells. We started talking about how our body natural pretects itself, things like barfing, sneezing, coughing, etc. We also talked about the immune system and germs. We talked about bacteria which are Uni-cellular organisms that can affect the human body in both a negative or positive way. Another type of germ we learned about was a virus. A virus is a multi-cellular organism that when it enters an organism it takes over, or infects, a cell that is already in the organisms body, usually in a negative way. Pathogen was another germ we talked about. When a bacteria affects you in a negative way (like a disease) , the bacteria is refered to as pathogen. You are probably wondering what your body does to prevent these things, well we learned about that to. Our first defence's are things like your skin, earwax,saliva, and gastric acids (in your stomach). They aren't very reliabal though because they will try to stop both negative and positive germs, and they don't stop every germ. The quicker your body can catch germs at this defence level, the better. Your body's second defence comes into play once germs get through the first defence and into the blood stream. The secondary defence is much more agressivethen the first. They can tell the differece between negative and positive germs and target all the negative germs.