What Cause Diseases? Chapter 18

What is a disease?

A disease is a condition that affects the proper functioning of the body or mind.

2 Types of diseases Communicable Noncommunicable Diseases that can spread. Example: the common cold Noncommunicable Diseases that do not spread Example: Cancer and Diabetes

Where do communicable disease come from?

Simply GERMS (aka Pathogens)

4 Classes of Pathogens Viruses 2. Bacteria 3. Protozoa 4. Fungi

How are these germs spread?

Does washing your hands really work??? Examples Direct contact (shaking hands) Indirect contact (sneezing, coughing) Eating or drinking contaminated food or liquid (sharing a drink/food) Contact with animals or insects (bites) Important terminology: Contagious- A disease that can be spread to others by direct or indirect contact. Does washing your hands really work???

What types of defenses does our body have?

How our body plays defense Skin (our 1st line of defense) Body Fluids (saliva, tears, etc.) Mucous Membranes- Tissues that line the inside of your mouth, throat, and nose. Coated with a sticky fluid called mucous which traps and destroys germs

If those don’t work… The Immune System Important parts: A group of cells, tissues, and organs that fight disease Important parts: Lymphocytes: white blood cells that attack harmful germs Antibodies: chemicals produced by lymphocytes to fight specific germs or diseases.

What about a vaccine? Dead or weakened germs introduced into your body. Why? This causes the immune system to make antibodies to fight a specific pathogen